JP3243991B2 - Additive-type heat-curable silicone elastomer composition for fixing roll and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a cured product which is cured by a hydrosilylation addition reaction and gives a cured product excellent in low hardness, high strength and low compression set. The present invention relates to an addition-type heat-curable silicone elastomer composition for a fixing roll, which is excellent in long life and fast-curing properties) and can be suitably used for a fixing roll of a PPC or a facsimile, and a method for producing the same.

[0002]

2. Description of the Related Art An addition-type heat-curable liquid silicone rubber contains an alkenyl group-containing organopolysiloxane, an organohydrogenpolysiloxane, and a platinum group metal compound as a curing catalyst. It is used in various fields because of its excellent heat resistance and excellent heat resistance and electrical insulation after molding. It is especially used for fixing rolls of PPC, LBP, FAX, etc. because of its excellent heat resistance and release properties. I have.

On the other hand, recently, since the size of the equipment has been reduced, the size of the roll has necessarily been reduced. For this reason, the roll material is required to provide a low-hardness product that does not impair the compression set and strength, which have been conventionally required characteristics, and that the rubber itself has low hardness in order to obtain a nip width.

Further, a liquid injection molding machine is often used as a molding method. Recently, a cold runner method has been used to reduce material loss or to perform automatic molding in addition to shortening a molding cycle by increasing a molding temperature for the purpose of cost reduction. A method of forming a large number of rolls at once is employed. In this molding method, curing in the mixing zone due to an increase in molding temperature and curing in the cold runner section are fatal, so a cooling device is usually used to prevent curing. Difficult, 60
The temperature may be around ℃. Therefore, it is important that the pot life at a relatively low temperature around 60 ° C. after mixing the alkenyl group-containing organopolysiloxane, organohydrogenpolysiloxane, and platinum group metal-based curing catalyst is long without impairing the curability. It is becoming.

[0005] For these reasons, in addition to the above-mentioned conventional properties, the rubber material to be used is required to have sufficient pot life after mixing and excellent curability as important properties. .

[0006] First, several methods for reducing the hardness are known. One of the methods is to lower the crosslink density, but this method has an adverse effect on compression set, strength and the like. Also known is a method of reducing the amount of filler as a filler, but this method has an adverse effect on strength,
When molded as a roll, thermal expansion and thermal shrinkage increase, which adversely affects the properties of the roll.

As a technique for realizing low compression set, Japanese Patent Application Laid-Open No. 4-139258 has proposed a method of using a specific cross-linking system. Although it is possible, there is a disadvantage that it is difficult to balance the pot life and the curability, which are important characteristics in the molding described above.

Further, in order to achieve high strength, it is common to use non-crystalline fillers, but these fillers have a considerable amount of active silanol groups on the surface, and are subjected to hydrophobic treatment. However, there is a disadvantage that the compression set cannot be completely eliminated, so that the compression set is considerably adversely affected.

Therefore, development of a silicone elastomer composition which does not have these problems and is suitable for a fixing roll is desired.

The present invention has been made to meet the above-mentioned demands, and provides a cured product having low hardness, high strength, and excellent compression set, and in particular, a fixing excellent in balance between curability and pot life. An object of the present invention is to provide an addition type heat-curable silicone elastomer composition for a roll and a method for producing the same.

[0011]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, (1) an aliphatic unsaturated hydrocarbon bonded to a silicon atom in one molecule. The aliphatic unsaturated hydrocarbon group-containing siloxane unit contains two or more groups only in the side chain of the molecule,
An organopolysiloxane of up to 5 mol%, and (2)
An organohydrogenpolysiloxane containing three or more hydrogen atoms bonded to silicon atoms at both ends and side chains of the molecule or in only one side chain in one molecule; (3) an average particle size of 0.1
２2 μm of crystalline silica and (4) a hydrosilylation reaction catalyst as main components, and part or all of the component (1) and the component (3) are heated and mixed at 70 to 190 ° C. in advance,
By mixing the mixture with other components, a cured product having excellent low hardness, high strength, and low compression set is obtained, and in particular, an addition-type heat-curable silicone for a fixing roll excellent in balance between curability and pot life. An elastomer composition was obtained, and it was found that this composition was suitable for PPC, facsimile fixing rolls, and the like, and the present invention was accomplished.

Accordingly, the present invention provides: (1) one molecule containing two or more aliphatic unsaturated hydrocarbon groups bonded to a silicon atom only in the side chain of the molecule, and containing the aliphatic unsaturated hydrocarbon group; The amount of siloxane unit is 0.05 to 5
(2) An organohydrogenpolysiloxane containing three or more hydrogen atoms bonded to silicon atoms in one molecule at both ends and side chains of the molecule, or only in the side chains. (2) Component The amount by which the molar ratio of the hydrogen atom bonded to the silicon atom in the compound to the aliphatic unsaturated hydrocarbon group bonded to the silicon atom of the organopolysiloxane of the component (1) is 5: 1 to 1: 5. Crystalline silica having a particle size of 0.1 to 2 µm 10 to 200 parts by weight based on 100 parts by weight of the total of the components (1) and (2) (4) Hydrosilylation reaction catalyst
A catalyst amount as a main component, and part or all of the component (1) and (3)
And an addition-type heat-curable silicone elastomer composition for a fixing roll, wherein the components have been previously heat-mixed, and part or all of the component (1) and (3)
The present invention provides a method for producing the above-mentioned addition-type heat-curable silicone elastomer composition for a fixing roll, in which components are preliminarily heated and mixed at 70 to 190 ° C, and then the mixture is mixed with other components.

Now, the present invention will be described in further detail. The first component of the addition-type heat-curable silicone elastomer composition for a fixing roll according to the present invention comprises an aliphatic unsaturated hydrocarbon bonded to a silicon atom in one molecule. An essentially linear diorganopolysiloxane containing two or more groups only in the side chains of the molecule (ie, only as substituents bonded to the silicon atoms of the diorganosiloxane unit), It is a component which becomes.

Here, as the organopolysiloxane, those represented by the following average molecular formula (1) can be suitably used.

[0015]

Embedded image (However, R ¹ is a substituted or unsubstituted monovalent hydrocarbon group other than an aliphatic unsaturated hydrocarbon group, R ² is a monovalent aliphatic unsaturated hydrocarbon group, and m and n are each m ≧ 38. , N ≧ 2,
40 ≦ m + n ≦ 20,000, preferably 100 ≦ m +
n ≦ 10,000, 0.05 ≦ [n / (m + n)] × 1
00 ≦ 5, preferably 0.1 ≦ [n / (m + n)] × 1
It is an integer satisfying 00 ≦ 3. )

In the above formula (1), R ¹ preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group,
Isopropyl group, butyl group, isobutyl group, tert-
Butyl group, hexyl group, cyclohexyl group, octyl group, alkyl group such as decyl group, aryl group such as phenyl group and tolyl group, aralkyl group such as benzyl group and phenylethyl group, and part or all of hydrogen of these groups Chloromethyl, bromoethyl, trifluoropropyl, and cyanoethyl groups in which atoms are substituted with a halogen atom such as chlorine, bromine, or fluorine or a cyano group, and the like, but a methyl group, a phenyl group, and a trifluoropropyl group are particularly preferable. .
R ² is an aliphatic unsaturated hydrocarbon group such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group or the like having 2 to 6 carbon atoms, particularly an alkenyl group having 2 to 4 carbon atoms. Particularly, a vinyl group is preferable.

In the above formula (1), the substituents may be different or the same, but the organopolysiloxane of the first component of the present invention contains only the side chain in the molecule (that is, R
¹ ) only ^two substituents R ² attached to the silicon atom of the diorganosiloxane unit represented by R ² SiO _2/2 ) containing two or more aliphatic unsaturated hydrocarbon groups, and an aliphatic unsaturated hydrocarbon The amount of the siloxane unit containing a group is 0.05 to
It needs to be 5 mol%, preferably 0.1 to 3 mol%. In the present invention, the amount (mol%) of the siloxane unit containing an aliphatic unsaturated hydrocarbon group is
Diorganosiloxane units constituting the main chain of the first component (i.e., R ¹ ₂ SiO _2/2 units and R ¹ R ² SiO _2/2 Total Units) aliphatic unsaturated group-containing siloxane units to (ie, R ¹ R ² SiO _2/2 unit). The content of the aliphatic unsaturated hydrocarbon group is 0.05 m
When the amount is less than 5 mol%, it is difficult to maintain physical properties of rubber such as mechanical strength, and when it exceeds 5 mol%, it is very difficult to obtain a cured product having low hardness.

Incidentally, this organopolysiloxane is
Generally, the main chain is basically a diorganosiloxane unit
(Ie, R¹ _TwoSiO_2/2Unit and R¹R^TwoSiO_2/2unit)
, And both ends of the molecular chain are triorganosiro
A xy group (ie, R¹ _ThreeSiO_1/2Unit)
Diorganopolysiloxane in the form of¹
SiO_3/2Unit, R^Two SiO_3/2Unit or SiO_4/2Units
It may be a branched shape or a ring shape.

The degree of polymerization (or the number of silicon atoms in the molecule) of the organopolysiloxane of the above formula (1) is 50.
20,000, especially 100-15,000, especially about 500-10,000 are suitable.

The second component used in the present invention comprises one molecule
Three or more hydrogen atoms (Si-H groups) bonded to silicon atoms
Ol molecules contained in both ends and side chains of the upper molecule or only in the side chains
Ganohydrogenpolysiloxane, the first component
It is a component that serves as a crosslinking agent for the organopolysiloxane. Book
In the invention, such a first component and a second component are combined.
To obtain a cured product with low hardness and low compression set.
be able to. In particular, the second component has a side chain (ie, R
^Three (H) SiO_2/2Monoorganohydrogen represented by
(As a siloxane unit)
Reaction activity is slightly low due to steric hindrance, etc.
-Terminal (ie, R^Three _Two(H) SiO_1/2Geo indicated by
Only in Lugano hydrogen siloxy units)
Potra after mixing compared to those having i-H groups
If can be further improved.

The organohydrogenpolysiloxane of the second component is represented by the following average molecular formula (2):
Basically, a linear one is suitably used.

[0022]

Embedded image (Provided that R ³ is a substituted or unsubstituted monovalent hydrocarbon group, R ⁴ is a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group, p is 0 or an integer of 1 or more, and q is 1 Integer of 1 or more, 1 ≦ p + q ≦ 300, preferably 3 ≦ p + q ≦ 1
00, which contains three or more Si-H groups in the molecule. )

In the above formula (2), R ³ and R ⁴ as an unsubstituted or substituted monovalent hydrocarbon group each preferably have 1 to 8 carbon atoms, more preferably 1 to 8 carbon atoms.
4 is a monovalent hydrocarbon group having no aliphatic unsaturated bond and similar to those exemplified as R ¹ above, for example, an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, and a phenyl group And chloromethyl, trifluoropropyl, and cyanoethyl groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms or cyano groups. The organohydrogenpolysiloxane is generally linear, but may have a partially branched skeleton or may be cyclic.

The above-mentioned organohydrogenpolysiloxane must contain at least three hydrogen atoms bonded to silicon atoms at both ends and side chains of the molecule, or at least three hydrogen atoms only in the side chains. H content is 0.0001-
0.02 mol / g, especially 0.0002 to 0.01 mo
A range of 1 / g is preferred. The amount of Si-H is 0.0001m
When the amount is less than ol / g, it is difficult to obtain a rubber cured product, and when it exceeds 0.02 mol / g, the hardness of the cured product cannot be reduced. The polymerization degree (or the number of silicon atoms in the molecule) of the organohydrogenpolysiloxane of the above formula (2) is preferably from 3 to 300, particularly preferably from about 5 to 100.

Examples of such an organohydrogenpolysiloxane include, for example, organohydrogenpolysiloxanes having a triorganosiloxy group at both ends of a molecular chain,
Triorganosiloxy group-blocked diorganosiloxane / organohydrogensiloxane copolymer at both ends of molecular chain, diorganohydrogensiloxy group-blocked organohydrogenpolysiloxane at both ends of molecular chain, diorganohydrogensiloxy group at both ends of molecular chain Examples thereof include an organosiloxane / organohydrogensiloxane copolymer (however, in the above, the organo group may be a methyl group, a phenyl group, or a trifluoropropyl group).

The amount of the organohydrogenpolysiloxane of the above formula (2) is determined by the amount of hydrogen atoms (ie, Si—H groups) bonded to silicon atoms in the molecule and silicon atoms of the first component organopolysiloxane. The molar ratio of the aliphatic unsaturated hydrocarbon groups to be bound is 5: 1 to 1: 5, particularly 2: 1 to 1:
When the molar ratio is out of the above range, curing is insufficient during curing or foaming occurs to obtain a cured product excellent in low compression set. It can be difficult.

The crystalline silica of the third component used in the present invention is an important component for developing high strength without adversely affecting the compression set of the cured elastomer, and has an average particle size of 0.1. 1-2 μm, preferably 0.3-1.8 μm
Use what is m. When the average particle size is less than 0.1 μm, the compression set is adversely affected, the viscosity of the elastomer composition changes with time, and the average particle size is 2 μm.
If it exceeds μm, high strength cannot be exhibited in the cured elastomer.

The amount of the crystalline silica is 10 to 200 parts by weight, preferably 50 to 150 parts by weight, based on 100 parts by weight of the total of the first component and the second component. When the amount is less than 10 parts by weight, it is difficult to exhibit sufficient mechanical strength in the cured product, and when it exceeds 200 parts by weight, the physical properties of the rubber are adversely affected.

The composition of the present invention further comprises an aliphatic unsaturated hydrocarbon group bonded to a silicon atom in the first component and a hydrogen atom bonded to a silicon atom in the second component (ie, a Si—H group). And a hydrosilylation reaction catalyst which acts as a catalyst for crosslinking the above by a hydrosilylation addition reaction.

In this case, as a compound that can be a catalyst for the hydrosilylation reaction, a known platinum group metal compound such as a platinum-based, rhodium-based, or palladium-based compound can be used. Among these, platinum-based catalysts such as platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, and complexes of chloroplatinic acid with olefins, aldehydes, vinylsiloxanes, and acetylene alcohols are preferable. These compounds can be used as they are, but they may be used after being diluted with a solvent such as alcohols, aromatic compounds, hydrocarbons, ketones, and chlorine compounds.

The amount of the hydrosilylation reaction catalyst to be added is as follows:
It can be a normal catalytic amount, especially platinum, palladium, when using a platinum group metal compound such as rhodium,
In terms of platinum group metal, 0.1 to 500 pp is usually contained in the composition.
m, preferably in a proportion such that it is contained in an amount of 1 to 100 ppm.

[0032] Other optional components can be added to the composition of the present invention as needed. Specifically, silica fine particles, fillers such as calcium carbonate, silicone-based resins as reinforcing agents, carbon black, conductive zinc powder, conductive powders such as metal powders, nitrogen-containing compounds and acetylenes such as acetylene alcohols. Hydrosilylation reaction control agents such as compounds, phosphorus compounds, nitrile compounds, carboxylate, tin compounds, mercury compounds, and sulfur compounds; heat-resistant agents such as iron oxide and cerium oxide; internal mold release agents such as dimethyl silicone oil; And a thixotropy-imparting agent. In addition, the addition amount of these optional components can be a usual amount as long as the effect of the present invention is not hindered.

In producing the addition type heat-curable silicone elastomer composition for a fixing roll of the present invention, a part or all of the organopolysiloxane of the first component and crystalline silica of the third component are previously mixed by heating. After preparing a product (hereinafter referred to as a base), the base is mixed with other components to produce the base.

In this case, the crystalline silica usually has an inert surface and a small reinforcing effect, but the reinforcing effect is exhibited by heating and mixing with the organopolysiloxane as in the present invention. That is, when this crystalline silica is blended with a part or all of the organopolysiloxane polymer of the first component as a main component, if kneaded by cold blending (that is, mixing by non-heat treatment), the final viscosity becomes high. And changes the viscosity over time, and also has an adverse effect on compression set. On the other hand, when a part or all of the first component and the third component are mixed by heating, the final viscosity decreases, the viscosity does not change with time, and the silanol groups on the silica surface are heated and mixed. It is considered that silanol groups, which are considered to remain in the polymer in a small amount, cause an interaction such as a chemical reaction, so that the tensile strength of the rubber after molding can be further improved as compared with the cold blend.

Here, the amount of the first component which is preliminarily heated and mixed with the crystalline silica of the third component is appropriately selected, but is preferably at least 50% by weight, more preferably at least 65% by weight of the entire first component. .

The temperature during the heating and mixing is 70 to 190.
C., particularly 100 to 170 ° C., and if the temperature is lower than 70 ° C., the treatment may not proceed well.
When the heat treatment is performed at a temperature higher than 0 ° C. for a long time, the organopolysiloxane of the first component as the main component may be deteriorated. The heating and mixing time is not particularly limited, but is preferably 30 minutes or more, particularly about 1 to 2 hours, from the viewpoint of processing degree and cost. In addition, mixing can be performed by a usual means using a mixer, a kneader, a three-roll mill, or the like.

Further, when producing the composition of the present invention, the above-mentioned base obtained by previously heating and mixing part or all of the first component and the third component is prepared. Agent A to which the remainder of the organopolysiloxane and the hydrosilylation reaction catalyst of the fourth component are added, and the above-mentioned base, the remainder of the organopolysiloxane of the first component, the organohydrogenpolysiloxane of the second component, and other components It is preferable to separately prepare the added B agent. These two agents can be mixed at the time of use, post-cured after press curing, and the conditions are not particularly limited. However, after press curing (primary curing) at 50 to 200 ° C. for 1 to 60 minutes, 150 to 250 ° C. And post-curing (secondary curing) for 1 to 6 hours.

[0038]

The addition type heat-curable silicone elastomer composition for a fixing roll of the present invention is cured by a hydrosilylation addition reaction to give a cured product having excellent low hardness, high strength and low compression set. It has an excellent balance between properties and pot life, and can be suitably used for fixing rolls of PPC and facsimile.

[0039]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Formulation Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. All parts in each example are parts by weight.

[Formulation Example 1] A linear dimethylpolysiloxane in which both ends of the molecular chain are blocked with trimethylsiloxy groups and containing an average of about 5 side-chain vinyl groups as methylvinylsiloxane units (polymerization degree: about 700, vinyl Price 0.009
100 parts of 4 mol / 100 g) and 85 parts of crystalline silica (average particle size: 1.5 μm) were mixed, mixed by heating under reduced pressure at 150 ° C. for 2 hours, and dispersed by three rolls (base 1).

[Formulation Example 2] 100 parts of dimethylpolysiloxane having a side chain vinyl group (polymerization degree: about 700, vinyl value: 0.0094 mol / 100 g), and crystalline silica (average particle size: 1.5 μm) as in Formulation Example 1 85 parts at room temperature (25 ° C)
And dispersed with three rolls (base 2).

Formulation Example 3 The same side chain vinyl group-containing dimethylpolysiloxane as in Formulation Example 1 (polymerization degree: about 700, vinyl value: 0.0094 mol / 100 g), 100 parts, and crystalline silica (average particle size: 5 μm), 85 parts Are mixed under reduced pressure.
The mixture was heated and mixed at 0 ° C. for 2 hours and dispersed with a three-roll mill (Base 3).

[Formulation Example 4] A linear dimethylpolysiloxane in which both ends of the molecular chain are blocked with vinyldimethylsiloxy groups (degree of polymerization: about 550, vinyl value: 0.00525 mol)
/ 100 g) 100 parts of crystalline silica (average particle size 1.5
μm), mixed by heating under reduced pressure at 150 ° C. for 2 hours, and dispersed by a three-roll mill (base 4).

Example 1 Base 1 obtained in Formulation Example 1
185 parts, 43 parts of the same side chain vinyl group-containing dimer polysiloxane as used in Formulation Example 1, a platinum catalyst (Pt
(Concentration 1%) was mixed with 1 part, and this was used as agent A. Base 1
185 parts, side chain vinyl group-containing dimethylpolysiloxane 37 parts used in Formulation Example 1, methyl hydrogen having Si—H groups at both molecular chain terminals and side chains represented by the following average molecular formula (A) as a crosslinking agent Polysiloxane (Si-
H amount 0.00308 mol / g) in 6.2 parts, 1,3
0.3 parts of 5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1-ethynyl-1-
0.35 parts of cyclohexanol was mixed, and this was used as agent B.

[0045]

Embedded image

Next, the agent A and the agent B were mixed in a ratio of 100 parts: 100 parts, and after press curing at 120 ° C. for 10 minutes,
Post-curing at 200 ° C for 4 hours to prepare a sheet and a sample for compression set, hardness, tensile strength, elongation,
Compression set (above, measured by a method according to JIS K6301), specific gravity, curability, and pot life were measured. The curability and pot life were measured by the following methods. Curability : Use a rheometer manufactured by Toyo Seiki Co., Ltd.
° C and a swing angle of 3 °.
The time at 10% in the case of% is T ₁₀ (seconds), 90
The time at% was T ₉₀ (seconds). Pot life : Using a Toyo Seiki rheometer,
Under the conditions of 60 ° C. and a swing angle of 3 °, the time until T ₀ (minute) of the rise was measured.

Example 2 A methyl hydrogen polysiloxane having a Si—H group only in the side chain represented by the following average molecular formula (B) as a crosslinking agent (Si—H content 0.001)
A sheet and a sample for compression set were prepared in the same manner as in Example 1 except that 18 parts (71 mol / g) were used, and the characteristics were measured as in Example 1.

[0048]

Embedded image

Comparative Example 1 Methyl hydrogen polysiloxane (Si-H content 0.00136 mol / g) having Si-H groups only at both molecular chain terminals represented by the following average molecular formula (C) was used as a crosslinking agent. A sheet and a sample for compression set were prepared in the same manner as in Example 1 except that some parts were used, and the characteristics were measured as in Example 1.

[0050]

Embedded image

[Comparative Example 2] As a cross-linking agent, 10.2 parts of methyl hydrogen polysiloxane having Si-H groups only at both ends similar to that used in Comparative Example 1 was used.
Further, 1-ethynyl- which is a hydrosilylation reaction control agent is used.
A sheet and a sample for compression set were prepared in the same manner as in Example 1 except that the amount of 1-cyclohexanol was changed to 0.6 part, and the characteristics were measured in the same manner as in Example 1.

[Comparative Example 3] Formulation Example 2 instead of Base 1
Example 1 except that 185 parts of the base 2 obtained in the above was used.
In the same manner as in Example 1, a sheet and a sample for compression set were prepared, and the characteristics were measured as in Example 1.

[Comparative Example 4] Formulation Example 3 instead of Base 1
Example 1 except that 185 parts of the base 3 obtained in the above were used.
In the same manner as in Example 1, a sheet and a sample for compression set were prepared, and the characteristics were measured as in Example 1.

[Comparative Example 5] Base 4 obtained in Formulation Example 4
Was mixed with 185 parts of the same dimethylpolysiloxane having vinyl dimethylsiloxy groups at both ends and 1 part of a platinum catalyst (Pt concentration: 1%) similar to that used in Formulation Example 4, and used as Agent A. In addition, 185 parts of base 4 were converted to 37 parts of dimethylpolysiloxane having a vinyldimethylsiloxy group at both ends similar to those used in Formulation Example 4, and both ends of molecular chains similar to those used in Example 1 as a crosslinking agent. S in the side chain
8.7 parts of methyl hydrogen polysiloxane having an i-H group, 1,3,5,7-tetramethyl-1,3,3
5,7-tetravinylcyclotetrasiloxane 0.3
And 0.35 parts of 1-ethynyl-1-cyclohexanol were mixed, and this was used as agent B.

Next, the above A agent: B agent was added in 100 parts: 100
And press-curing at 120 ° C. for 10 minutes, followed by post-curing at 200 ° C. for 4 hours to prepare a sheet and a sample for compression set, and the characteristics were measured in the same manner as in Example 1.

Table 1 shows the above results. From the results in Table 1, it was confirmed that the composition of the present invention had low hardness, high strength, low compression set, and excellent properties such as long pot life and fast curing.

[0057]

[Table 1] *) JIS A is A-type hardness tester, Asker C is Asker C
Value measured by a type hardness tester.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 83/07 C08K 3/36 C08L 83/05

Claims (2)

(57) [Claims] (1) The amount of a siloxane unit containing two or more aliphatic unsaturated hydrocarbon groups bonded to a silicon atom in one molecule only in the side chain of the molecule, and (2) an organohydrogenpolysiloxane containing three or more hydrogen atoms bonded to silicon atoms in one molecule at both ends and side chains of the molecule, or only in the side chains. Siloxane The molar ratio of the hydrogen atom bonded to the silicon atom in the component (2) to the aliphatic unsaturated hydrocarbon group bonded to the silicon atom in the organopolysiloxane of the component (1) is 5: 1 to 1: 5. Amount (3) Crystalline silica having an average particle size of 0.1 to 2 μm 10 to 200 parts by weight based on 100 parts by weight of the total of components (1) and (2) (4) Hydrosilylation reaction catalyst
An addition-type heat-curable silicone elastomer composition for a fixing roll, characterized in that a catalyst amount is a main component, and a part or all of the component (1) and the component (3) are heat-mixed in advance. . 2. The fixing roll according to claim 1, wherein a part or all of the component (1) and the component (3) are preliminarily heated and mixed at 70 to 190 ° C., and then the mixture is mixed with other components. A method for producing a heat-curable silicone elastomer composition.