JPH09286922A - Curable composition and roller using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a curable composition capable of inhibiting the elevation in the hardness of a molded product in spite of the charging of an inorganic filler and further capable of enhancing thermal conductivity to shorten the curing time of the molded product by charging the electrically insulating metal oxide. SOLUTION: This curable composition is obtained by adding (A) an electrically insulating metal oxide, preferably either one of beryllium oxide, magnesium oxide and aluminum oxide, especially surface-coupled magnesium oxide to a resin composition capable of being cured by a hydrosilylation reaction. The curable composition preferably further contains (B) a polymer having alkenyl groups in the molecule and containing oxyalkylene units as the repeating units of the main chain, (C) a compound having at least two hydroxyl groups in the molecule and (D) a hydrosilylation catalyst. The component A is preferably added in an amount of 20-200 pts.wt. per 100 pts.wt. of the component B.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid injection molding,
The present invention relates to a curable composition used for obtaining an elastic body such as a roller by casting a liquid resin in a mold and curing it, and more specifically, a curable composition which is cured by a reaction between an alkenyl group and a hydrosilyl group and The present invention relates to a roller manufactured by using the roller.

[0002]

2. Description of the Related Art In a process of casting a liquid resin into a mold or the like and heating and curing it, heat conduction is rate-determining, and a difference occurs between a resin temperature near the inner surface of the mold and a resin temperature inside the mold, There is a problem that the resin inside does not cure easily. This problem becomes particularly noticeable when molding a thick molded body.

When the set temperature of a heat source such as a mold is raised in order to solve the problem of curing delay due to heat conduction, the resin temperature near the heat source becomes higher than the decomposition temperature, and resin burns due to decomposition, gas generation, etc. Happens. On the other hand, if the addition amount of the storage stability improver is reduced for the purpose of rapidly advancing the hydrosilylation reaction on the low temperature side, there arises a problem that the pot life of the resin becomes short.

There is also a method of increasing the thermal conductivity of the composition by filling an inorganic filler such as silica, but in many cases, the hardness of the cured product increases more than the thermal conductivity,
The resulting molded article loses good elasticity and flexibility. For example, when it is used for a rubber roller of an electrophotographic machine, good softness is lost, which causes a defective image with a reduced nip width. Moreover, when a large amount of inorganic filler is filled, the hydrosilylation catalyst is poisoned more than the thermal conductivity is increased, and as a result, the curing time is often lengthened.

[0005]

SUMMARY OF THE INVENTION In view of the above points, the present invention involves casting a liquid resin, which is cured by a hydrosilylation reaction, into a mold and heat-curing it to form an elastic body.
Aiming to improve the thermal conductivity and shorten the curing time of the curable composition at the time of molding without increasing the hardness of the molded product and without shortening the pot life of the composition. To do.

[0006]

[Means for Solving the Problems] Among the various prior arts for shortening the curing time as described above, the inventors of the present invention suppress the increase in hardness of a molded product even if an inorganic filler is filled. As a result of intensive studies to obtain a curable composition capable of increasing the thermal conductivity and shortening the curing time, filling with an electrically insulating metal oxide, preferably an oxide such as magnesium, aluminum or beryllium. Has been found to be effective. Also, considering the balance of toxicity, cost, hardness increase, etc., Agnesium oxide is preferable, and further, in the point that the catalyst is not poisoned even if a large amount is filled, the filling of magnesium oxide surface-treated with a coupling agent is the most preferable. I found it preferable.

The present invention has been made based on the above findings. That is, the present invention

A curable composition characterized in that (A) an electrically insulating metal oxide is filled in a resin composition cured by a hydrosilylation reaction (claim 1),

A curable composition (claim 2) in which the metal oxide (A) is at least one selected from the group consisting of beryllium oxide, magnesium oxide, and aluminum oxide.

A curable composition (claim 3) in which the metal oxide (A) is magnesium oxide;

(A) Magnesium oxide, (B) a polymer having an alkenyl group in the molecule, and the main chain repeating unit is an oxyalkylene unit, and (C) at least 2 in the molecule.
Curable composition containing a compound having one hydrosilyl group and (D) a hydrosilylation catalyst (claim 4),

[0012] Magnesium oxide as the component (A) is contained in an amount of 20 to 200 parts by weight per 100 parts by weight of the component (B) (claim 5), and the surface of the magnesium oxide is coupled. A curable composition which has been treated with an agent (claim 6),

An elastic molded body (claim 7) obtained by casting the curable composition according to any one of claims 1 to 6 in a mold and curing by heating.

Further, a roller (claim 8) obtained by thermoforming the curable composition according to any one of claims 1 to 6.
The contents are as follows.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition used in the present invention is not particularly limited as long as it is a curable composition which is thermally cured by a hydrosilylation reaction, and the main chain of the polymer as the component (B) is repeated. Examples of the unit include polysiloxane-based, saturated hydrocarbon-based, oxyalkylene-based, and the like.
An oxyalkylene type is used because of its low hardness.

In the present invention, as the component (A), an electrically insulating metal oxide is used in order to increase the thermal conductivity without increasing the hardness of the molded product. Among them, the point of greatly increasing the thermal conductivity. The oxide of beryllium, aluminum or magnesium is preferable, and magnesium oxide is more preferable because it has a large effect of suppressing the increase in hardness of the molded product and is low in cost. The metal oxide as the component (A) is added in an amount of 50 with respect to 100 parts by weight of the component (B) in the composition.
When it is added in an amount of more than 1 part by weight, it is preferable that the content of impurities is small in order not to poison the catalyst. It is more preferable that the surface is treated with a coupling agent.
The coupling agent used for the surface treatment is not particularly limited as long as it is not poisoned by the catalyst, but a silane coupling agent is preferable from the viewpoint of easy availability, and there are vinylsilane-based, epoxysilane-based, aminosilane-based, etc. From the viewpoint of poison, vinylsilane type and epoxysilane type are preferable. The metal oxide used in the present invention is electrically insulating as described above,
It is completely different from a conductive metal oxide which is generally used as a conductivity-imparting agent and has a specific resistance of 10 ⁵ Ω · cm or less obtained by doping a metal oxide.

Next, the curable composition according to the present invention is
(A) magnesium oxide, (B) a polymer having an alkenyl group in the molecule and a repeating unit of the main chain of which is an oxyalkylene unit, (C) a compound having at least two hydrosilyl groups in the molecule, and In the case of containing (D) a hydrosilylation catalyst (curable composition according to claim 4)
Will be described.

As the curable composition, the above (B) to (D)
When a roller is manufactured using a resin composition containing the components, it is possible to manufacture a roller characterized by low hardness, low compression set, and a small amount of conductivity-imparting agent in bleeding.

First, the component (B), which is a polymer having an alkenyl group in the molecule and a repeating unit of the main chain of which is an oxyalkylene unit, is a component which undergoes a hydrosilylation reaction with the component (C) and cures. is there.

The main chain of component (B) is active as a starting material.
Compounds having two or more hydrogens, such as ethylene glycol
, Propylene glycol, bisphenol compound
Products, glycerin, trimethylolpropane, pentaery
Use a stall, etc._Two~ C _FourAlkylene oxide
It is manufactured by polymerizing. Made in this way
Specific examples of the polymer constituting the main chain to be produced are
For example, polyethylene oxide, polypropylene oxy
, Polybutylene oxide, ethylene oxide, propylene
2 selected from lenoxide and butylene oxide
Examples include more than one type of random or block copolymers.
It is.

Specific examples of the polymer (component (B)) having an alkenyl group in the molecule and the repeating unit constituting the main chain being an oxyalkylene unit include a cured product having a low hardness and a liquid composition. It is preferable that the repeating unit of the main chain has an oxypropylene unit from the viewpoint that it is easy to obtain, and when water absorption is required, a copolymer in which a part of the oxypropylene unit is changed to an oxyethylene unit Is preferred.

The molecular weight of the component (B) is a number average molecular weight (Mn) from the viewpoint of balance between reactivity and low hardness.
500 to 50,000, and further 1,000 to 20,
000, especially 5,000 to 10,000 is preferable.

From the viewpoint of rubber elasticity, the number of alkenyl groups contained in the component (B) is preferably at both ends of the molecule, and preferably at both ends of the linear molecule. , And the number is preferably two.

Next, the component (C) in the curable composition is
It is a component that acts as a curing agent for the component (B).

The component (C) contains at least 2 in the molecule.
There is no particular limitation as long as it is a compound having one hydrosilyl group, but the number of hydrosilyl groups contained in the molecule is 2
From the viewpoint of controlling the rubber properties of the cured product and storage stability, it is preferably 50 to 50, and more preferably 2 to 30, and more preferably 5 to 30, especially 15 to 25. It is preferable that the number of hydrosilyl groups is 3 to 20 from the viewpoint that foaming during curing can be easily prevented.
When the number of the hydrosilyl groups is less than 2, the curing speed when the curable composition is cured by the hydrosilylation reaction becomes slow and the curing failure often occurs.
Further, when the number of hydrosilyl groups exceeds 50,
The stability of the curing agent as the component (C), and thus the stability of the curable composition, tends to deteriorate, and in addition, a large amount of hydrosilyl groups tend to remain in the cured product even after curing, resulting in voids and cracks. It becomes easy to cause.

The term "having one hydrosilyl group" usually means having one SiH. However, when a plurality of Hs are bonded to the same Si, for example, SiH is used.
_In the case of ₂ , it is said to have two hydrosilyl groups. The plurality of Hs bonded to Si may be bonded to different Sis, or the plurality of Hs may be bonded to the same Si. However, bonding to different Sis is better in curability, and Also, it is preferable in terms of rubber elasticity.

The molecular weight of the component (C) is 30,000 as the number average molecular weight (Mn) in view of the dispersibility of carbon black and inorganic filler used, roller processability, etc., if necessary.
It is preferably 0 or less, more preferably 20,000 or less, and particularly preferably 15,000 or less. Considering the reactivity and compatibility with the component (B), it is 300 to 10,0.
00 is more preferred.

The structure of the component (C) as described above is not particularly limited, but for example, the general formula (1): R ¹ X _a (1) (wherein, X is a group containing at least one hydrosilyl group). , R ¹ is a monovalent to tetravalent hydrocarbon group having 2 to 150 carbon atoms,
a is an integer selected from 1 to 4, provided that when X contains only one hydrosilyl group, a is 2 or more) and has a number average molecular weight of 30,000 or less. A specific example is a hydrocarbon-based curing agent contained therein.

In the general formula (1), X represents a group containing at least one hydrosilyl group. Specific examples thereof include --SiH _n (CH ₃ ) _3-n (where n =
_{1~3), - SiH n (C} 2 H 5) 3-n ( provided that, n =
_{1~3), - SiH n (C} 6 H 5) 3-n ( provided that, n =
1-3), - such as _{SiH 2 (C 6 H 13)} , hydrosilyl group containing only one silicon atom,

[0030]

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A hydrosilyl group containing two or more silicon atoms, such as

[0032]

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[0033]

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[0034]

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Examples thereof include hydrosilyl groups derived from various chain-like, branched-like, and cyclic polyvalent hydrogen siloxanes. In the formula, m units and p units, n units and q units, m units and p units and x units, n units and q units, It is described that y units, m units and n units, and further, m units, n units, p units, and q units are connected by block bonding. However, these may be block bonds or random bonds. The same applies to the following description.

Of the various hydrosilyl groups mentioned above,
Since the hydrosilyl group-containing hydrocarbon-based curing agent as the component (C) is less likely to impair the compatibility with other organic polymers, the molecular weight of the part constituting the hydrosilyl group is 5
It is preferably at most 00, and in consideration of the reactivity of the hydrosilyl group, the following is preferred.

[0037]

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Hereinafter, these groups will be referred to as "groups represented by (Chemical Formula 5)".

Further, in the general formula (1), R ¹ represents a monovalent to tetravalent hydrocarbon group having 2 to 150 carbon atoms, which may be a polymer group. As a specific example,

[0040]

[Chemical 6]

[0041]

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(Note that these are disclosed in JP-A-3-9526.
No. 6, etc.), and specific examples of the group in which R ¹ is a polymer include ethylene, propylene,
A polymer obtained by polymerizing an olefinic compound having 2 to 6 carbon atoms such as 1-butene, isobutylene or the like as a main monomer, having 1 to 4 bonds, or a diene-based compound such as butadiene or isoprene alone. Polymerizing,
The olefin-based compound and the diene-based compound are copolymerized and then hydrogenated, and examples thereof include those having 1 to 4 bonds.

Among the hydrocarbon type curing agents represented by the general formula (1) having R ¹ and X as described above, R ¹ is a hydrocarbon group having 5 to 20 carbon atoms and X is the above-mentioned (formula 5). The combination in the case of the groups shown increases the reactivity,
It is preferable from the viewpoint of compatibility with the component (B). Among these, it is preferable that R ¹ is a hydrocarbon group having 5 to 12 carbon atoms from the viewpoint of easily obtaining the raw material, and X
Is preferably a cyclic polysiloxane compound among the groups represented by (Chemical Formula 5) from the viewpoint of better compatibility with the component (B). The compound obtained by this combination is preferable as the hydrocarbon-based curing agent. For example, for example,

[0044]

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And the like.

The method for producing the hydrosilyl group-containing hydrocarbon-based curing agent which is the component (C) is not particularly limited and may be produced by any method.

For example, (i) a molecule containing a SiCl group
Hydrocarbon curing agent, LiAlH _Four, NaBH_FourSuch
To reduce the SiCl groups in the curing agent to SiH groups
(Ii) functional group X in the molecule¹Also
A hydrocarbon compound and the functional group X in the molecule¹React with
Functional group Y¹And compounds having both hydrosilyl groups
Method of reacting with a substance, (iii) containing an alkenyl group
To at least two hydro-hydrocarbon compounds
Select a polyhydrosilane compound having a silyl group
By hydrolyzing, the hydrosilyl group can be converted to
Examples include methods of leaving hydrogen hydride compounds in the molecule.
Is done.

Of the above methods, the method (iii) can be preferably used because the manufacturing process is generally simple.
In this case, two or more of the hydrosilyl groups of some polyhydrosilane compounds may react with the alkenyl groups of the hydrocarbon-based compound to increase the molecular weight, but those containing such increased molecular weight ( It may be used as the component C).

A polysiloxane-based curing agent can also be used as the component (C). Specific examples include the following linear or cyclic polyorganohydrogensiloxanes (including modified polyoxyalkylenes, modified styrenes, modified olefins, and the like).

[0050]

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(M and n are integers, 10≤m + n≤50, 2
≦ m, 0 ≦ n, R is a methyl group, and the molecular weight is 100 to 10,
000 polyoxyalkylene group or 2-20 carbon atoms
The above hydrocarbon group may contain one or more phenyl groups. When a plurality of Rs are included, they need not be the same. )

[0052]

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(M and n are integers, 10≤m + n≤50, 2
≦ m, 0 ≦ n, R is a methyl group, and the molecular weight is 100 to 10,
000 polyoxyalkylene group or 2-20 carbon atoms
The above hydrocarbon group may contain one or more phenyl groups. When a plurality of Rs are included, they need not be the same. )

[0054]

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(M and n are integers, 3≤m + n≤20, 2≤
m ≦ 19, 0 ≦ n ≦ 18, R is methyl group, molecular weight is 10
The polyoxyalkylene group may have 0 to 10,000 or a hydrocarbon group having 2 to 20 carbon atoms and may contain one or more phenyl groups. When a plurality of Rs are included, they need not be the same. )

In order to improve the compatibility with the component (B), it is preferable that R contains a phenyl group. Further, from the availability, -CH ₂ -CH
_{2 -C 6 H 5, -CH 2} -CH (CH 3) -C 6 H
_5, also from the viewpoint of storage stability, -CH ₂ -CH (C
H ₃₎ -C ₆ H ₅ are preferred.

The ratio of the component (B) and the component (C) used is such that the ratio of the number of alkenyl groups in the component (B) to the number of hydrosilyl groups in the component (C) (alkenyl group / hydrosilyl group) is 0. 0.5 to 2.0, more preferably 0.7 to 1.5, good gum elasticity can be obtained.
It is preferable in that there is little blizzard of unreacted material.

In the curable composition of the present invention, the hydrosilylation catalyst which is the component (D) is used together with the components (B) and (C).

The hydrosilylation catalyst which is the component (D) is not particularly limited, and specific examples thereof include solid platinum supported on a carrier such as platinum, alumina, silica, carbon black, chloroplatinic acid, Complexes of chloroplatinic acid with alcohols, aldehydes, ketones, platinum /
Examples thereof include an olefin complex and a platinum / phosphite complex.

The amount of such a hydrosilylation catalyst used is 1 mol per 1 mol of the alkenyl group in the component (B).
It is preferably from 0 ^-1 to 10 ^-6 mol, more preferably from 10 ^-3 to 10 ^-6 mol from the viewpoint of prevention of curing inhibition due to catalyst poisoning and appropriate balance of pot life and cost.

Further, in the curable composition of the present invention, in addition to the above-mentioned components (A) to (D), a storage stability improving agent, for example, a compound containing an aliphatic unsaturated bond, an organic phosphorus compound,
Organic sulfur compounds, nitrogen-containing compounds, tin compounds, organic peroxides, etc. may be added. As a concrete example,
Examples include, but are not limited to, benzothiazole, thiazole, dimethyl maleate, dimethyl acetylenedicarbochelate, 2-pentenenitrile, 2,3-dichloropropene, quinoline and the like. Among these, thiazole, benzothiazole, and dimethylmalate are particularly preferable from the viewpoint of compatibility of pot life and rapid curing property. The storage stability improvers may be used alone or in combination of two or more.

The curable composition of the present invention is often used for conductive rollers among rollers, and carbon black, dentol (manufactured by Otsuka Chemical Co., Ltd.), pastran (manufactured by Mitsui Kinzoku Co., Ltd.), Typake ET, Typake It is often used by adding a conductive metal oxide such as FT (manufactured by Ishihara Sangyo).

Further, the curable composition of the present invention may contain a filler, a storage stabilizer, a plasticizer, an ultraviolet absorber, a lubricant, a pigment and the like for improving processability and cost.

The curable composition of the present invention comprising the components (B) to (D) as described above, and a composition to which a component such as carbon black, which is optionally used, is added, is made of, for example, SUS. 80-150 ° C, preferably 10
Various types of rollers or papers to be used in contact with a photoconductor of an electronic copying machine or printer by heating and curing at a temperature of about 0 to 140 ° C. for 1 hour to 10 seconds, preferably 20 to 1 minute It can be molded into rollers. In this case, after semi-curing, post-curing may be performed.

[0065]

【Example】

(Examples 1 to 7 and Comparative Examples 1 to 3) Length 250 m
m, a width of 100 mm, and a height of 40 mm, two S55C plates were put together, and a mother die for a heat source, which was hollowed into a cylindrical shape having a diameter of 22 mm across both plates, was set to 140 ° C. with a cartridge heater. . Insert a metal shaft with an outer diameter of 8 mm into a pipe-shaped mold with an outer diameter of 22 mm and an inner diameter of 16 mm,
After preheating in the mother die for 1 minute, the curable composition shown in the following Table 1 was poured into the die over about 1 minute and thermally cured.

[0066]

[Table 1]

Table 2 shows the hardness and the curing time of the above cured product.

[0068]

[Table 2]

As is clear from the results in Table 2, Comparative Example 2
Although the curing completion time can be shortened, the hardness of the cured product is significantly increased. On the other hand, in Examples 1 to 4, 6, and 7, compared with Comparative Example 1, and in Example 5 as compared with Comparative Example 3, the increase in hardness of the cured product was very slight. Nevertheless, the curing time is shortened in each case.

Example 8 A roller having a diameter of 12 mm was formed from a curable composition obtained by adding 0.5 part by weight of Ketjen Black EC to the curable composition of Example 4 described above, and a roller having a diameter of 12 mm was formed on the surface thereof.
A polyamide solution (a methanol solution of a system obtained by adding 10 parts by weight of Elecut S-512 manufactured by Takemoto Yushi Co., Ltd. to 100 parts by weight of CM-8000 manufactured by Toray) is spray-applied, and
After drying at 0 ° C. for 1 hour, the roller surface was protected with a polyamide layer of about 30 μm. The resistance of the obtained roller with a protective layer is
It was 2 × 10 ⁶ ohm as measured by applying a DC voltage of 100 V with a load of 500 g on both ends. Also, this roller
A good result was obtained by setting the charging roller position of FC-310 manufactured by Canon Inc. and conducting an image output test.

Claims (8)

[Claims] 1. A curable composition characterized in that a resin composition cured by a hydrosilylation reaction is filled with (A) an electrically insulating metal oxide. 2. The curable composition according to claim 1, wherein the metal oxide (A) is at least one selected from the group consisting of beryllium oxide, magnesium oxide, and aluminum oxide. . 3. The curable composition according to claim 1, wherein the metal oxide (A) is magnesium oxide. 4. A polymer having (A) magnesium oxide, (B) a polymer having an alkenyl group in the molecule and having a main chain repeating unit being an oxyalkylene unit, and (C) at least two hydrosilyl groups in the molecule. Curable composition containing the compound which has, and (D) hydrosilylation catalyst. 5. The curable composition according to claim 4, wherein the component (A), magnesium oxide, is contained in an amount of 20 to 200 parts by weight based on 100 parts by weight of the component (B). 6. The curable composition according to claim 3, wherein the surface of magnesium oxide is treated with a coupling agent. 7. An elastic molded body obtained by casting the curable composition according to any one of claims 1 to 6 in a mold and curing by heating. 8. A roller obtained by thermoforming the curable composition according to claim 1.