(19)
(11)EP 2 125 955 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
21.10.2015 Bulletin 2015/43

(21)Application number: 07851129.2

(22)Date of filing:  20.12.2007
(51)International Patent Classification (IPC): 
C08L 83/04(2006.01)
C08K 5/24(2006.01)
C08K 5/00(2006.01)
C08K 5/34(2006.01)
(86)International application number:
PCT/JP2007/075335
(87)International publication number:
WO 2008/081952 (10.07.2008 Gazette  2008/28)

(54)

ADDITION-REACTION-CURABLE SILICONE RUBBER COMPOSITION AND A MOLDED ARTICLE THEREFROM

ADDITIONSHÄRTBARE SILICONGUMMIZUSAMMENSETZUNG UND GEFORMTER ARTIKEL DARAUS

COMPOSITION DE CAOUTCHOUC SILICONE DURCISSABLE PAR RÉACTION D'ADDITION ET ARTICLE MOULÉ À BASE DE CE CAOUTCHOUC


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE SI SK TR

(30)Priority: 27.12.2006 JP 2006352469

(43)Date of publication of application:
02.12.2009 Bulletin 2009/49

(73)Proprietor: Dow Corning Toray Co., Ltd.
Tokyo, 100-0004 (JP)

(72)Inventor:
  • IRIE, Masakazu
    Ichihara-shi Chiba 2990108 (JP)

(74)Representative: Busher, Samantha Jane et al
Elkington and Fife LLP 3-4 Holborn Circus
London, EC1N 2HA
London, EC1N 2HA (GB)


(56)References cited: : 
EP-A- 0 731 131
US-A1- 2006 040 116
EP-A- 0 822 234
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical Field



    [0001] The present invention relates to an addition-reaction curable silicone rubber composition that is suitable for forming a molded article which has low compression set without secondary heat treatment after primary curing.

    Background Art



    [0002] An addition-reaction curable silicone rubber composition that contains silicon-bonded hydrogen atoms and silicon-bonded alkenyl groups and is curable by a hydrosilylation reaction in the presence of a hydrosilylation catalyst is known in the art. The above composition can be easily handled and can be cured at a lower temperature and during a shorter time than a radical-reaction curable silicone rubber composition and therefore finds application for manufacturing parts used in office-automation equipment, automobiles, and in other fields of industry. However, when the parts formed from the aforementioned composition operate over long time under conditions of high compression stress, they develop high compression set. In order to reduce these deformations, the aforementioned parts have to be subjected to secondary heat treatment, and this creates significant obstacles for improvement of productivity.

    [0003] Heretofore, several compositions that contain various organic compounds aimed at the solution of the above problem have been proposed. For example, it was proposed to use an organopolysiloxane rubber composition curable by an addition reaction and compounded with a phthalocyanine compound (see Japanese Unexamined Patent Application Publication (hereafter referred to as "Kokai") H3-146560 (equivalent to US5153244)). However, articles molded from an organopolysiloxane rubber composition curable by an addition reaction and compounded with a phthalocyanine compound have limited practical application because of coloration caused by the phthalocyanine.

    [0004] Furthermore, Kokai 2006-56986 (equivalent to US2006-0040116A1) discloses a two-part liquid type curable silicone composition that contains a triazole-based compound or an amidazole-based compound and that is characterized by low compression set. However, triazole-type compounds, such as benzotriazole, are characterized either by extremely slow speed of curing of silicone rubber compositions of the type curable by addition reaction, or by an unpleasant odor emitted during thermal molding of the aforementioned composition. US 2006/040116 discloses a two-part curable silicone composition including: (A) 100 parts by mass of an organopolysiloxane containing at least two alkenyl groups bonded to silicon atoms, (B) an organohydrogenpolysiloxane containing at least two SiH groups, in sufficient quantity to provide from 0.5 to 5.0 mols of SiH groups within the component (B) for every 1 mol of alkenyl groups within the entire composition, (C) an effective quantity of a hydrosilylation reaction catalyst, and (D) from 0.0001 to 1 part by mass of a nitrogen-containing compound (a triazole-based compound and/or an imidazole-based compound), which is prepared in two separate parts, in which the components (A) through (C) do not exist within one part, and the component (D) exists in a different part from that of the component (C).
    EP 0 731 131 discloses a heat-curable silicone rubber composition comprising (a) an organopolysiloxane having at least two alkenyl groups in a molecule, (b) an organohydrogenpolysiloxane having at least two hydrogen atoms in a molecule, and (c) a platinum catalyst is added (d) ammonia or an ammonia precursor so that ammonia or ammonia precursor is present in an amount of 10 to 500 parts by weight of nitrogen per million parts by weight of the total of components (a), (b) and (c) in a cured product of the heat-curable silicone rubber composition.
    EP 0 822 234 discloses an addition-crosslinkable silicone rubber composition comprising the constituents (I) an alkenyl-functional polyorganosiloxane (II) a SiH-functional crosslinker (III) a hydrosilylation catalyst and (IV) at least one 1H-benzotriazole-5-carboxylic acid derivative selected from a group consisting of 1H-benzotriazole-5-carboxylic acid esters and 1H-benzotriazole-5-carboxylic acid amides.

    Disclosure of Invention



    [0005] It is an object of the present invention to provide an addition-reaction curable silicone rubber composition that is suitable for forming a molded article which has low compression set and does not need secondary heat treatment after primary curing.

    [0006] The addition-reaction curable silicone rubber composition of the invention comprises: 0.001 to 5 mass % of a metal deactivator selected from a diacyl-hydrazide-based compound, an aminotriazole-based compound, or an amino-containing triazine-based compound; and 0.001 to 5 mass % of a compound used as a curing-retarder selected from an acetylene-containing silane, an enyne compound, a vinyl-containing low-molecular-weight organosiloxane compound, or an alcohol derivative having carbon-carbon triple bonds; wherein the diacylhydrazide-based compound is represented by the following general formula (1):

    where R1 and R2 may be the same or different and are each independently represented by a hydrogen atom, a hydroxyl group, an alkyl group, a substituted alkyl group, an aryl group, a phenol group or similar substituted aryl group, an aralkyl group, or a substituted aralkyl group;
    the aminotriazole-based compound is expressed by the following general formula (2):

    where R4 is a hydrogen atom, an alkyl group, a substituted alkyl group, a substituted aryl group, a carboxyl group, an acyl group, an alkyl-ester group, an aryl-ester group, a halogen, or an alkali metal, R3 is a hydrogen atom or an acyl group, and R5 is an acyl group; and the amino-containing triazine-based compound is 2,4,6-triamino-1,3,5-triazine.

    [0007] Since the addition-reaction curable silicone rubber composition of the invention contains a metal deactivator, it becomes suitable for forming articles molded from silicone rubber, which are not subject to coloration and have low compression set without need of secondary heat treatment after primary curing. Furthermore, provision of the metal deactivator eliminates delay in speed of curing.

    Best Mode for Carrying Out the Invention



    [0008] The addition-reaction curable silicone rubber composition of the invention contains a metal deactivator and a curing-retarder selected from an alcohol derivative having carbon-carbon triple bonds, an enyne compound, vinyl-containing low-molecular-weight organosiloxane, and acetylene-containing silane.

    [0009] The aforementioned metal deactivator is the most specific component of the composition of the present invention. It is an indispensable component needed for imparting low compression set to a molded article obtained by curing the addition-reaction-curable silicone rubber composition of the invention without need in secondary heat treatment.

    [0010] The metal deactivator is selected from a diacylhydrazide-based compound, an aminotriazole-based compound, and an amino-containing triazine-based compound, especially the diacylhydrazide-based compound, which is readily available and is easily dispersible in the silicone rubber composition.

    [0011] The diacylhydrazide-based compound is represented by the following general formula (1):

    where R1 and R2 may be the same or different and may be represented by hydrogen atoms, hydroxyl groups, alkyl groups, substituted alkyl groups, aryl groups, phenol groups or similar substituted aryl groups, aralkyl groups, or substituted aralkyl groups. It is preferable that R1 and R2 comprise monovalent hydrocarbon groups that contain aryl groups, a phenol or a similar substituted aryl group.

    [0012] More specific examples of the aforementioned diacylhydrazide-based compounds are the following: N,N'-diformyl hydrazine, N,N'-diacetyl hydrazine, N,N'-dipropionyl hydrazine, N,N'-butylyl hydrazine, N-formyl-N'-acetyl hydrazine, N,N'-dibenzoyl hydrazine, N,N'-ditolyoyl hydrazine, N,N'-disalicyloyl hydrazine, N-formyl-N'- disalicyloyl hydrazine, N-formyl-N'-butyl-substituted salicyloyl hydrazine, N-acetyl-N'- salicyloyl hydrazine, N,N'-bis [3-(3,5-di-t-butyl-4-hydroxyphenyl) propyonyl] hydrazine, oxalic acid -di-(N'-salicyloyl) hydrazine, adipic acid di-(N'-salicyloyl) hydrazine, or dodecane dioyl-di-(N'-salicyloyl) hydrazine. Commercially produce compounds of the aforementioned type are the following: Irganox MD1024 (trademark of Ciba Specialty Chemicals Co., Ltd.): N,N'-bis -[3-(3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine), or Adekastab CDA-6 (trademark of Adeka Co., Ltd.; dodcadioyl-di-(N'-salicyloyl) hydrazine).

    [0013] The aminotriazole-based compound is expressed by the following general formula (2):

    where R4 is a hydrogen atom, an alkyl group, a substituted alkyl group, a substituted aryl group, a carboxyl group, an acyl group, an alkyl-ester group, an aryl-ester group, a halogen, or an alkali metal; R3 is a hydrogen atom or an acyl group; and R5 is an acyl group, preferably, a salicyloyl group, benzoyl group, or a similar acyl group having an aromatic ring.

    [0014] Specific examples of the aforementioned compounds are the following: 3-amino-1,2,4-triazole, 3-amino-1,2,4-triazole-carboxylic acid, 3-amino-5-methyl-1,2,4-triazol, 3-amino-5-heptyl-1,2,4-triazol, etc.; or an acid amide derivative of an amino-triazole-based compound where the hydrogen atoms of a triazole-bonded amino groups are substituted with acyl groups, e.g., 3-(N-salicyloyl) amino-1,2,4-triazole or 3-(N-acetyl) amino-1,2,4-triazol-5-carboxylic acid. Most preferable among the above compounds is the acid amide derivative of the aminotriazole-based compound since this compound does not delay speed of curing of the addition-reaction-curable silicone rubber composition. An example of a commercially produced compound of this type is Adekastab CDA-1 (trademark of Adeka Co., Ltd.: 3-(N-salicyloyl) amino-1,2,4-triazole).

    [0015] The amino-containing triazine-based compound is 2,4,6-triamino-1,3,5-triazine. An example of a commercially available compound of this type is Adekastab ZS-27 (trademark of Adeka Co., Ltd.: main component is 2,4,6-triamino-1,3,5-triazine).

    [0016] The metal deactivator is added in an amount of 0.001 to 5 parts by mass per 100 parts by mass of component (A). If this agent is added in the amount of less than 0.001, the effect of decrease in compression set will be too low. If, on the other hand, this agent is added in an amount exceeding 5 parts by mass, this will be economically unjustifiable, and in some cases may lead to discoloration of the molded product.

    [0017] The aforementioned curing-retarder is a component that is used for adjusting the relationship between speed of curing and storability to enable to use of the composition. Specific examples of the aforementioned compounds are the following: 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, phenylbutynol, 1-ethynyl-1-cyclohexanol, or a similar alcohol derivative having carbon-carbon triple bonds; 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, or a similar enyne; tetramethyltetravinyl cyclotetrasiloxane, tetramethyltetrahexenyl cyclotetrasiloxane, or a similar alkenyl-containing siloxane of low molecular weight;1-methyl-tris (3-methyl-1-butyn-3-oxy) silane, or vinyl-tris(3-methyl-1-butyn-3-oxy) silane, or a similar alkyne-containing silane.

    [0018] The amount in which the curing-retarder is added to the composition of the invention is selected with reference to the method of molding and use of the addition-reaction-curable silicone rubber composition. In general, however, this agent should be used in the amount ranging from 0.001 to 5 mass %.

    [0019] The addition-reaction-curable silicone rubber composition of the invention may comprise a conventional millable-type addition-reaction-curable silicone rubber composition, and preferably, a liquid-type addition-reaction-curable silicone rubber composition which normally comprises an organopolysiloxane (A) having in one molecule at least two alkenyl groups, an organohydrogenpolysiloxane (B) having in one molecule at least two silicon-bonded hydrogen atoms, a hydrosilylation-reaction catalyst (C), the aforementioned metal deactivator, and the aforementioned curing-retarder.

    [0020] Organopolysiloxane (A), which is one of main components of the silicone rubber composition, has in one molecule at least two silicon-bonded alkenyl groups. The alkenyl groups can be represented by vinyl, allyl, propenyl, or similar groups. This component may contain organic groups other than alkenyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, or similar alkyl groups; phenyl, tolyl, or similar aryl groups; β-phenylethyl, or similar aralkyl groups; or 3,3,3-trifluoropropyl, 3-chloropropyl, or similar halogenated alkyl groups. Component (A) may have a linear, partially branched linear, cyclic, or a net-like molecular structure. Component (A) may be combined with two or more different types of the aforementioned organopolysiloxanes. There are no special restrictions with regard to molecular weight of component (A), and this component may be used in various forms ranging from low-viscous liquids to highly viscous gum-like state organopolysiloxane. However, in order to obtain a cured composition in the form a rubberlike resilient body, it is recommended that the viscosity of component (A) be equal to or greater than 100 mPa·s at 25°C.

    [0021] The organohydrogenpolysiloxane (B) is a cross-linking agent of the silicone rubber composition of the present invention. In the presence of hydrosilylation-reaction catalyst (C), this component promotes cross-linking and curing of the composition as a result of an addition reaction between the silicon-bonded alkenyl groups of component (A) and the silicon-bonded hydrogen atoms of component (B). The organohydrogenpolysiloxane of component (B) contains in one molecule at least two silicon-bonded hydrogen atoms. Organic groups other than the silicone-bonded hydrogen atoms may be represented by methyl, ethyl, propyl, or similar alkyl groups; phenyl, tolyl, or similar aryl groups; 3,3,3-trifluoropropyl, or 3-chloropropyl, or similar substituted alkyl groups. Component (B) may have a linear, partially branched, cyclic, or a net-like molecular structure. Organohydrogenpolysiloxanes of two or more different types can be used in combination.

    [0022] There arc no special restrictions with regard to the viscosity of component (B), and this component may have viscosity ranging from 3 to 10,000 centipoises at 25°C. In the composition of the present invention, component (B) can be used in an amount such that the ratio of the mole number of the silicon-bonded hydrogen atoms of the composition to the mole number of the silicon-bonded alkenyl groups is maintained in the range of (0.5 : 1) to

    [0023] (20 : 1), preferably (1 : 1) to (3:1). If the mole number of the silicon-bonded hydrogen atoms contained in the composition is less than 0.5 per 1 mole of the silicon-bonded alkenyl groups contained in the composition, then the latter can be insufficiently cured, and if, on the other hand, the mole number of the silicon-bonded hydrogen atoms exceeds 20 per 1 mole of the silicon-bonded alkenyl groups contained in the composition, this may cause formation of foaming in the cured body.

    [0024] Hydrosilylation-reaction catalyst (C) is used as a catalyst for curing the addition-reaction type silicone rubber composition of the invention. The hydrosilylation-reaction catalyst of component (C) may be the same as conventional catalysts used for the same purpose and can be exemplified by chloroplatinic acid, an alcohol solution of chloroplatinic acid, an olefin complex of chloroplatinic acid, complexes with vinyl siloxanes or acetylene compounds, platinum black, platinum on a solid carrier, or other platinum-based catalysts; tetrakis-(triphenylphosphine) palladium, or similar palladium-based catalysts; or a chloro-tris (triphenylphosphine) rhodium-based catalyst. The catalyst of component (C) should be used in the amount of 0.1 to 500 parts by mass, preferably 1 to 50 pats by mass in terms of the catalytic metal per 106 parts by mass of the total mass of components (A) and (B). If component (C) is used in the amount less than 0.1 parts by mass, curing will be insufficient, and if, on the other hand, it is used in the amount exceeding 500 parts by mass, this will become economically unjustifiable.

    [0025] In order to adjust flowability of the composition and to improve mechanical strength of a molded body, the silicone rubber composition of the present invention can be combined with additives normally added to silicone rubber, such as, e.g., precipitated silica, fumed silica, baked silica, fumed titanium oxide, or a similar reinforcement filler; crushed quartz, crystalline silica, diatomaceous earth, asbestos, aluminosilicic acid, iron oxide, zinc oxide, calcium carbonate, or a similar non-reinforcement filler, or the aforementioned fillers surface treated with an organosilane, an organopolysiloxane, or a similar organosilicon compounds. The composition can be combined with acetylene black, furnace black, channel black, or a similar carbon black. If necessary, the composition may incorporate pigments, heat-resistant agents, flame retarders, mold-release agents, plasticizers, acid acceptors, non-functional silicone oils, or other similar additives normally used in conjunction with silicone rubber compositions.

    [0026] The silicone rubber composition of the invention is easily prepared by uniformly mixing the aforementioned composition components, if necessary, together with appropriate additives. Mixing is carried out with the use of known mixing and kneading equipment such as a Ross mixer, two-roll mill, kneader-mixer, or the like.

    [0027] The silicone rubber composition of the invention can be molded by conventional molding methods, such as, e.g., injection molding, extrusion, or compression molding.

    Examples



    [0028] The invention will be further described more specifically with reference to practical and comparative examples. It is understood that these examples should not be construed as limiting the scope of the invention. Characteristics of the silicone rubber compositions were measured according to the provisions of respective Japanese Industrial Standards (JIS) as described below. All values of viscosity were measured at 25°C.

    <Curing Properties>



    [0029] These properties were measured in accordance with JIS K 6300-2 that stipulates conditions for the flexural vibration-type flat-plate die vulcanization test. In this test, IP designates "induction period" and is represented by time (sec.) to the point at which increase of the torque is detected. T90 designates the time (sec.) which is required to reach 90% of the maximum torque which is assumed as the torque developed 3 minutes after initiation of the test. Instances where curing was impossible are designated by symbol NA (Not Applicable).

    <Density>



    [0030] This characteristic was measured in accordance with JIS K 6268.

    <Hardness>



    [0031] This characteristic was measured by a typc-A durometer in accordance with JIS K 6253.

    <Tensile Strength and Elongation at Rupture>



    [0032] This characteristic was measured in accordance with JIS K 6251.

    <Compression Sct>



    [0033] In accordance with JIS K 6262, compression set was measured after 22 hours of 25% compression at 180°C.

    <Color>



    [0034] Color of a molded product was evaluated by visual observation.

    [Preparation Example 1]



    [0035] A Ross mixer was loaded with the following components: 100 parts by mass of a dimethylpolysiloxane having a viscosity of 40,000 mPa·s and capped at both molecular terminals with dimethylvinylsiloxy groups; 40 parts by mass of fumed silica having BET specific area of 225 m2/g; 7 parts by mass of hexamethyl disilazane; 2 parts by mass of water, and 0.2 parts by mass of a copolymer of a dimethylsiloxane and methylvinylsiloxane having viscosity of 20 mPa·s and capped at both molecular terminals with dimethylhydroxysiloxy groups (content of vinyl groups: about 10.9 mass %). The components were mixed and then heat treated for 2 hours at 200°C under reduced pressure. As a result, a flowable silica master batch was prepared.

    [Practical Examples 1 to 6 and Comparative Examples 1 to 5]



    [0036] Ingredients shown in Tables 1 and 2 were mixed to uniform mixture conditions at 25°C in a Ross mixer in the proportions indicated in the aforementioned tables. The obtained silicone rubber compositions were cured in a transfer press for 10 min. at 120°C, whereby specimens for testing compression set and rubber sheets for measuring various properties were produced. The obtained specimens and rubber sheets were used for measuring density, hardness, tensile strength, elongation, and compression set, as well as for visual evaluation of color. The results of measurements and observations are shown in Tables 1 and 2.
    Table 1
     Practical Examples
    123456
    Silica master batch 100 100 100 100 100 100
      (parts by mass)            
    Organopolysiloxane (A)            
    a-1 (parts by mass) 20 20 20 20 20 20
    Organohydrogenpolysiloxane (B)            
    b-1 (parts by mass) 2.9 2.9 2.9 2.9 2.9 2.9
    platinum-based catalyst (C) 0.08 0.08 0.08 0.08 0.08 0.08
      (parts by mass)            
    (d) Metal deactivator            
    d-1 (parts by mass) 0.2          
    d-2 (parts by mass)       0.1 0.03 0.01
    d-3 (parts by mass)   0.2        
    d-4 (parts by mass)     0.2      
    Curing-retarder (parts by mass) 1 1 1 1 1 1
    Curing properties            
    (3 min at 130°C)            
      IP (sec) 23 23 23 23 22 22
      T90 (sec) 36 34 32 37 38 35
    Density (g/cm3) 1.12 1.12 1.12 1.12 1.12 1.12
    Hardness (JIS-A) 49 50 51 49 49 51
    Tensile strength (MPa) 7.9 8.7 8.3 8.5 8.9 9.3
    Elongation (%) 350 400 360 420 450 450
    Compression Set (%) 28.0 22.6 24.4 17.9 16.6 30.2
    Color   Semi-transparent
    Table 2
     Comparative Examples
    12345
    Silica master batch (parts by mass) 100 100 100 100 100
    Organopolysiloxane (A)          
    a-1 (parts by mass) 20 20 20 20 20
    Organohydrogenpolysiloxane (B)          
    b-1 (parts by mass) 2.9 2.9 2.9 2.9 2.9
    Platinum-based catalyst (C) 0.08 0.08 0.08 0.08 0.08
      (parts by mass)          
    Phthalocyanine compound          
      (parts by mass)   0.2      
    Benzotriazole solution     0.02 0.04 0.67
      (parts by mass)          
    Curing-retarder (parts by mass) 1 1 1 1 1
    Curing properties (3 min at 130°C)          
      IP (sec) 23 22 22 23 NA
      T90 (sec) 38 33 44 61 NA
    Density (g/cm3) 1.12 1.12 1.12 1.12 NA
    Hardness (JIS-A) 51 49 49 52 NA
    Tensile strength (MPa) 10.5 9.1 10.2 10 NA
    Elongation (%) 450 430 474 430 NA
    Compression Set (%) 79.0 22.5 46.8 54.2 NA
    Color Semitransparent Blue Semitransparent NA


    [0037] Designations used in Tables 1 and 2 have the following meanings:

    <Silica Master Batch>



    [0038] This is the silica master batch prepared in Preparation Example 1: contains about 27 mass % of fumed silica

    <Component A: Organopolysiloxane>



    [0039] a-1: Copolymer of methylvinylsiloxane and dimethylsiloxane that has viscosity of 350 mPa·s and is capped at both molecular terminals with dimethylvinylsiloxy groups: content of vinyl groups of about 1.17 mass %

    <Component B: Organohydrogenpolysiloxane>



    [0040] b-1: Copolymer of methylhydrogensiloxane and dimethylsiloxane, which is capped at both molecular terminals with trimethylsiloxy groups and has kinematic viscosity of 15 mm2/sec; content of silicon-bonded hydrogen atoms of about 0.83 mass %

    <Component C> Hydrosilylation-Reaction Catalyst>



    [0041] 1,3-divinyltetramethyldisiloxane solution of a platinum complex of 1,3-divinyltetramethyldisiloxane: 6,800 ppm content of metallic platinum

    <Metal deactivator>



    [0042] 

    d-1: Trademark - "Irganox" MD-1024:

    N,N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine (the product of Ciba Specialty Chemicals Co., Ltd.)

    d-2: trademark "Adekastab" CDA-1:

    3-(N-salicyloyl) amino-1,2,4-triazole (the product of Adeka Co., Ltd.)

    d-3: trademark "Adekastab" CDA-6:

    dodecanedioyl-di-(N'-salicyloyl) hydrazine (the product of Adeka Co., Ltd.)

    d-4: trademark "Adekastab" ZS-27:

    a mixture the main component of which is 2,4,6-triamino-1,3,5-triazine (the product of Adeka Co., Ltd.)


    <Phthalocyanine Compound>



    [0043] Copper phthalocyanine: trademark "Rionol Blue FG-7330 (the product of Toyo Ink Co., Ltd.)

    <Benzotriazole Solution>



    [0044] Isopropyl alcohol (IPA) solution of benzotriazole with 30 mass % content of benzotriazole

    <Curing-retarder>



    [0045] A mixture of 2 parts by mass of ethynyl cyclohexanol and 98 parts by mass of a dimethylpolysiloxane that is capped at both molecular terminals with dimethylvinylsiloxy groups and has viscosity of 10,000 mPa·s.

    Industrial Applicability



    [0046] Since, as has been shown above, the composition of the present invention possesses excellent moldability and after being molded produces a cured body that has low compression set, this composition is suitable for manufacturing parts capable of operating over a long time under conditions of compression stress, such as packings, rubber plugs, seal rings, or similar parts employed in automobiles, construction elements, parts of electric and electronic devices, etc. Furthermore, since the composition is suitable for molding parts that provide low compression set without use of secondary heat treatment, the composition is suitable for the manufacture of composite parts, e.g., co-molded parts produced from thermoplastics and silicone rubber compositions.


    Claims

    1. An addition-reaction-curable silicone rubber composition comprising:

    0.001 to 5 mass % of a metal deactivator selected from a diacyl-hydrazide-based compound, an aminotriazole-based compound, and an amino-containing triazine-based compound; and

    0.001 to 5 mass % of a curing-retarder selected from an alcohol derivative having carbon-carbon triple bonds, an enyne compound, an alkenyl-containing low-molecular-weight organosiloxane compound, or an alkyne-containing silane;

    wherein the diacylhydrazide-based compound is represented by the following general formula (1):

    where R1 and R2 may be the same or different and are each independently represented by a hydrogen atom, a hydroxyl group, an alkyl group, a substituted alkyl group, an aryl group, a phenol group or similar substituted aryl group, an aralkyl group, or a substituted aralkyl group;
    the aminotriazole-based compound is expressed by the following general formula (2):

    where R4 is a hydrogen atom, an alkyl group, a substituted alkyl group, a substituted aryl group, a carboxyl group, an acyl group, an alkyl-ester group, an aryl-ester group, a halogen, or an alkali metal, R3 is a hydrogen atom or an acyl group, and R5 is an acyl group; and
    the amino-containing triazine-based compound is 2,4,6-triamino-1,3,5-triazine.
     
    2. The addition-reaction-curable silicone rubber composition of Claim 1, wherein the aforementioned metal deactivator is a diacylhydrazide-based compound.
     
    3. The addition-reaction-curable silicone rubber composition of Claim 1 further comprising: (A)an organopolysiloxane having in one molecule at least two alkenyl groups; (B) an organohydrogenpolysiloxane having in one molecule at least two silicon-bonded hydrogen atoms; and (C) a hydrosilylation-reaction catalyst.
     
    4. The addition-reaction-curable silicone rubber composition of Claim 3, wherein the organopolysiloxane has a viscosity equal to or greater than 100 mPa.s at 25°C.
     
    5. A molded article obtained by curing the addition-reaction-curable silicone rubber composition according to any of Claims from 1 to 4.
     
    6. A method to obtain a molded product characterized by curing the addition-reaction-curable silicone rubber composition according to any of Claims from 1 to 4.
     


    Ansprüche

    1. Durch Additionsreaktion härtbare Silikongummizusammensetzung, umfassend:

    0,001 bis 5 Masse-% eines Metalldeaktivators, ausgewählt aus einer Diacylhydrazid-basierten Verbindung, einer Aminotriazol-basierten Verbindung und einer aminohaltigen Triazin-basierten Verbindung; und 0,001 bis 5 Masse-% eines Härtungsverzögerers, ausgewählt aus einem Alkoholderivat mit Kohlenstoff-Kohlenstoff-Dreifachbindungen, einer Enynverbindung, einer alkenylhaltigen niedermolekularen Organosiloxan-Verbindung oder einem alkyrihaltigen Silan;

    wobei die Diacylhydrazid-basierte Verbindung dargestellt wird durch die folgende allgemeine Formel (1):

    worin R1 und R2 gleich oder unterschiedlich sein können und jeweils unabhängig dargestellt werden durch ein Wasserstoffatom, eine Hydroxylgruppe, eine Alkylgruppe, eine substituierte Alkylgruppe, eine Arylgruppe, eine Phenolgruppe oder eine ähnliche substituierte Arylgruppe, eine Aralkylgruppe oder eine substituierte Aralkylgruppe;
    die Aminotriazol-basierte Verbindung ausgedrückt wird durch die folgende allgemeine Formel (2):

    worin R4 ein Wasserstoffatom, eine Alkylgruppe, eine substituierte Alkylgruppe, eine substituierte Arylgruppe, eine Carboxylgruppe, eine Acylgruppe, eine Alkylestergruppe, eine Arylestergruppe, ein Halogen oder ein Alkalimetall ist, R3 ein Wasserstoffatom oder eine Acylgruppe ist und R5 eine Acylgruppe ist; und die aminohaltige Triazin-basierte Verbindung 2,4,6-Triamino-1,3,5-triazin ist.
     
    2. Durch Additionsreaktion härtbare Silikongummizusammensetzung nach Anspruch 1, wobei der oben erwähnte Metalldeaktivator eine Diacylhydrazid-basierte Verbindung ist.
     
    3. Durch Additionsreaktion härtbare Silikongummizusammensetzung nach Anspruch 1, ferner umfassend:

    (A) ein Organopolysiloxan, das in einem Molekül mindestens zwei Alkenylgruppen aufweist; (B) ein Organohydrogenpolysiloxan, das in einem Molekül mindestens zwei siliciumgebundene Wasserstoffatome aufweist; und (C) einen Katalysator für eine Hydrosilylierungsreaktion.


     
    4. Durch Additionsreaktion härtbare Silikongummizusammensetzung nach Anspruch 3, wobei das Organopolysiloxan eine Viskosität von gleich oder größer als 100 mPa.s bei 25 °C aufweist.
     
    5. Formartikel, erhalten durch Aushärten der durch Additionsreaktion härtbaren Silikongummizusammensetzung nach einem der Ansprüche 1 bis 4.
     
    6. Verfahren zum Erhalten eines Formprodukts, gekennzeichnet durch Aushärten der durch Additionsreaktion härtbaren Silikongummizusammensetzung nach einem der Ansprüche 1 bis 4.
     


    Revendications

    1. Composition de caoutchouc de silicone durcissable par réaction d'addition, comprenant :

    0,001 à 5 % en masse d'un désactivateur de métaux choisi parmi un composé à base de diacylhydrazide, un composé à base d'aminotriazole, et un composé à base de triazine contenant un amino ; et 0,001 à 5 % en masse d'un ralentisseur de durcissement choisi parmi un dérivé d'alcool possédant des triples liaisons carbone-carbone, un composé ényne, un composé organosiloxane à faible masse moléculaire contenant un alcényle, ou un silane contenant un alcyne ;

    dans laquelle le composé à base de diacylhydrazide est représenté par la formule générale suivante (1) :

    où R1 et R2 peuvent être identiques ou différents et sont chacun indépendamment représentés par un atome d'hydrogène, un groupe hydroxyle, un groupe alkyle, un groupe alkyle substitué, un groupe aryle, un groupe phénol ou groupe aryle substitué similaire, un groupe aralkyle, ou un groupe aralkyle substitué ;
    le composé à base d'aminotriazole est exprimé par la formule générale suivante (2) :



    où R4 est un atome d'hydrogène, un groupe alkyle, un groupe alkyle substitué, un groupe aryle substitué, un groupe carboxyle, un groupe acyle, un groupe ester d'alkyle, un groupe ester d'aryle, un halogène, ou un métal alcalin, R3 est un atome d'hydrogène ou un groupe acyle, et R5 est un groupe acyle ; et le composé à base de triazine contenant un amino est la 2,4,6-triamino-1,3,5-triazine.
     
    2. Composition de caoutchouc de silicone durcissable par réaction d'addition selon la revendication 1, dans laquelle le désactivateur de métaux susmentionné est un composé à base de diacylhydrazide.
     
    3. Composition de caoutchouc de silicone durcissable par réaction d'addition selon la revendication 1, comprenant en outre :

    (A) un organopolysiloxane possédant dans une molécule au moins deux groupes alcényle ; (B) un organohydrogénopolysiloxane possédant dans une molécule au moins deux atomes d'hydrogène liés à du silicium ; et (C) un catalyseur de réaction d'hydrosilylation.


     
    4. Composition de caoutchouc de silicone durcissable par réaction d'addition selon la revendication 3, dans laquelle le organopolysiloxane a une viscosité égale ou supérieure à 100 mPa.s à 25 °C.
     
    5. Article moulé obtenu par durcissement de la composition de caoutchouc de silicone durcissable par réaction d'addition selon l'une quelconque des revendications 1 à 4.
     
    6. Procédé pour obtenir un produit moulé caractérisé par le durcissement de la composition de caoutchouc de silicone durcissable par réaction d'addition selon l'une quelconque des revendications 1 à 4.
     






    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description