JPS5850610B2 - Curable molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curable molding material, and its purpose is to provide a curable molding material that has a fast curing rate, a low shrinkage rate, and is easy to form into a solid material, has good mold release and flow, and can be molded. The purpose of the present invention is to provide a curable molding material with good properties.

In general, 1,2-polybutadienes have excellent electrical properties, but they have the drawbacks of slow curing speed, large mold shrinkage, and the tendency to turn into a solid state (and can only be made into a so-called putty-like material).

In order to overcome this drawback, it is possible to graft styrene or the like and react it with a metal oxide.
The material obtained in this manner has the disadvantage of poor fluidity and mold releasability, resulting in poor surface condition of the molded product.

The present invention was completed as a result of various studies in view of the above situation, and will be described in detail below.

The present invention uses 1,2-polybutadiene with a molecular weight of 100
0 to 4000, 1/2 bond is butadiene unit 50
% or more, preferably 80% or more of 1,2-polybutadiene glycol, and after reacting this 1,2-polybutadiene glycol with a vinyl monomer in the presence of a polymerization initiator such as an organic peroxide. After decomposing the remaining polymerization initiator with an accelerator and removing unreacted vinyl monomer from the system while raising the temperature under reduced pressure, an inorganic acid such as maleic anhydride is added at a temperature of 50 to 130°C. A resin component that is half-esterified by reacting a saturated dibasic acid anhydride and a grafted product is used.

Here, the amount of grafting is 0.05 to 0.3 per pendant 12 double bond of 1,2-polybutadiene glycol.
mol, preferably in the range of 0.1 to 0.2 mol.

This means that the amount of grafting is 0.0 per pendant double bond.
If it is less than 5 moles, there will be almost no effect of improving curing properties and molding shrinkage, and if it is more than 0.3 moles, the viscosity will be too low and it will become insoluble in solvents, so it will be difficult to perform half-esterification reaction process, take-out process, and reaction pot cleaning process. This is because it becomes difficult to do so.

Further, as the vinyl monomer to be grafted, for example, the following can be used.

(a) Styrene and its derivatives styrene, nuclear-substituted alkylstyrene (methylstyrene,
Dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, butylstyrene, t-butylstyrene), nuclear-substituted alkoxystyrene (methoxystyrene), α-methylstyrene, halogenated styrene (chlorostyrene, dichlorostyrene, flom) (2) Acrylic acid and its derivatives Acrylic acid, acrylic esters (methyl acrylate, etc.), methacrylic acid, methacrylic esters (methyl methacrylate, butyl methacrylate, etc.), etc. ) to acrylonitrile, methacrylonitrile, etc.)
Vinyl acetate These vinyl monomers are used in a ratio of 0.1 to 1.0 mol per mol of the above-mentioned two pendants.

Examples of polymerization initiators for the grafting reaction include organic peroxides such as benzoyl peroxide, t-butyl perbenzoate, di-t-butyl perbenzoate, cumene hydroperoxide, dicumyl peroxide, and methyl ethyl ketone peroxide. , azobisisobutyroni), etc. are used.

Furthermore, dimethylaniline, diethylaniline, etc. are used as polymerization accelerators.

The resin component is synthesized as follows.

First, 1,2-polybutadiene glycol and vinyl monomer are placed in a reaction vessel, a polymerization initiator is added thereto under an inert gas atmosphere, and the polymerization is carried out by heating.

The vinyl monomer may be added dropwise.

Further, a polymerization accelerator may be added if necessary.

The amount of polymerization initiator used is 0.1 to 1% by weight based on the total amount of 1,2-polybutadiene glycol and vinyl monomer.
may be used, but is not limited to this range.

Further, the reaction temperature for this grafting is 50 to 100°C, and the reaction time is 2 to 20 hours.

After the reaction, the remaining polymerization initiator is decomposed with a polymerization accelerator.

After the polymerization initiator is decomposed, a polymerization inhibitor (hydroquinone, benzoquinone, t-butylcatechol, etc.) is added as required, and unreacted vinyl monomer is recovered by heating under reduced pressure.

Next, a half-esterification reaction is performed.

Examples of α/β-unsaturated dibasic acid anhydrides used in this reaction include maleic anhydride, chloromaleic anhydride, citraconic anhydride, and 1,2 diethylmaleic anhydride. Add 0.5 to 2.0 mol per 1 mol of 1,2-polybutadiene glycol and reaction temperature 50
Synthesis is carried out at ~120°C and reaction time of 30 minutes to 5 hours.

Further, a solvent may be used in the esterification reaction if necessary.

Further, unsaturated polyester, metal compound, filler, reinforcing material, polymerization initiator, etc. are added to the obtained reaction product.

Unsaturated polyesters include glycols such as ethylene glycol, diethylene glycol, and chloropylene glycol, and α/β-unsaturated dibasic acids, either alone or in part, such as phthalic acid, phthalic anhydride, isophthalic acid, etc. It is obtained by substituting with a saturated dibasic acid and reacting by a known method.

Although the amount added is not particularly limited, it is preferably from 10 to the half-esterified 1,2-polybutadiene of the present invention], O0
%.

This is because if the O content is 0% or more, the electrical properties of 1,2-polybutadiene are lost, and if the O content is below 10%, there is no effect of improving so-called moldability such as fluidity or curability.

Metal compounds include oxides, hydroxides, and acetates of monovalent and divalent metals, and magnesium oxide is particularly preferred.

The amount of these metal compounds used is determined by the half-esterification reaction.
The amount is preferably 0.4 to 1.5 equivalents based on the total number of terminal carboxyl groups produced and the terminal carboxyl groups of the unsaturated polyester.

Examples of fillers include Merck, clay, silica, alumina, and alumina, and examples of reinforcing materials include glass fiber, asbestos fiber, vinylon, and nylon.

These are usually mixed using a kneader or rolls, but in order to suppress initial thickening and make kneading easier, methanol and
Alcohols such as ethanol, butanol, and isopropyl alcohol may also be added.

The present invention improves the shrinkage rate and curability by grafting vinyl monomers such as styrene monomers onto 1,2-polybutadiene glycol, and further improves α/β-
By reacting an unsaturated dibasic acid anhydride to half-esterify it and reacting the terminal carboxyl group with a metal compound, the curability and solidity were particularly improved, and by adding an unsaturated polyester to this, the moldability was improved. It is something.

The present invention will be specifically described below based on examples.

Example 1-1,2-polybutadiene glycol (PB manufactured by Nippon Soda Co., Ltd.
G100O) 100 parts, styrene monomer 80 parts, benzoyl peroxide 0.3 part, dimethylaniline 0.
In the formulation of 015, the styrene monomer and dimethylaniline were reacted dropwise at 80° C. for 5 hours to obtain a graft reaction product (styrene reaction rate 45%).

Styrene was removed from this graft reaction product and the mixture was reacted with 10 parts of maleic anhydride to obtain a resin (4) having an acid value of 33.

Next, 311 parts of propylene glycol, 2 parts of maleic anhydride
93 parts of isophthalic acid and 332 parts of isophthalic acid were placed in a reaction vessel, 200 PPm of hydroquinone was added to the total amount, and the temperature was raised to 220°C in 8 hours while dehydrating, to form an unsaturated polyester (resin B) with an acid value of 28. Obtained.

Using the resins (4) and (B) thus obtained, the resin (
A) 21 parts resin color)
9 parts glass fiber
20 Part Irrigation Alumina
50 parts zinc stearate 2.
5 parts dicumyl peroxide 1.5
The mixture was kneaded in a heated kneader at 80° C. at a ratio of 0.34 parts magnesium oxide, cooled, and further crushed in a crusher to obtain a granular molding material that was solid at room temperature.

Using this molding material, 150 kg/crj, 160
It was molded using a JIS K6911 contraction mold under molding conditions of 13 minutes at °C.

Furthermore, in order to investigate the curing speed, the curing time was measured using a curelastometer manufactured by Japan Synthetic Rubber Co., Ltd. at 160° C. and 1100 kg/crA.

Furthermore, as a simple method, plating was performed at 160℃ and 10oC.
A rice cracker-shaped molded product was molded under the conditions of kg/crtf, 20 seconds.

The results are shown in the table below. Example 2 The graft reaction between 1,2-polybutadiene glycol and styrene was carried out using the same formulation as in Example 1, and after de-styrene was carried out, 9 parts of maleic anhydride was reacted to produce resin C) with an acid value of 35. I got it.

Next, 31.1 parts of propylene glycol, 34 parts of fumaric acid
8 parts of isophthalic acid, 116 parts of phthalic anhydride, and 444 parts of phthalic anhydride were placed in a reaction vessel, and 200 ppm of hydroquinone was added to the total amount, and the mixture was heated to 210°C for 8 hours while dehydrating.
Resin 0 with an acid value of 35 was obtained.

Using these resins (C) and 0, resin, resin (C) 16.8
0 parts resin 11.2 parts glass fiber 15 parts calcium carbonate 57 parts calcium stearate 2.3 parts dicumyl peroxide
1.2 parts magnesium oxide 0.
The mixture was blended in a proportion of 32 parts, kneaded in a heated kneader at 70°C, cooled, and coarsely crushed in a crusher to obtain a dry material that is solid at room temperature.

150 kg/ct of this material! It was molded using a JIS K6911 shrinkage mold under molding conditions of 170° C. and 3 minutes.

Furthermore, in order to investigate the curing property, the curing time was measured at 170° C. and 100 kg/c4 using a curelastometer manufactured by Nippon Synthetic Rubber Co., Ltd.

Furthermore, as a simple method, a rice cracker-shaped molded product was molded under the same conditions as in Example 1.

The results are shown in the table below. Example 3 1,2-polybutadiene glycol (PB manufactured by Nippon Soda Co., Ltd.
G2000), 80 parts of styrene monomer, and 0.38 part of benzoyl peroxide were charged into a reaction vessel and reacted at 80° C. for 6 hours to obtain a graft polymer with a styrene conversion rate of 43%.

After removing styrene from this graft polymer, 67 parts of maleic anhydride was added and reacted to obtain a resin (2) having an acid value of 27.

Resin @ 20 parts Resin 0 5 parts Glass fiber
10 parts silica
15 Part Irrigation Alumina 50
Part zinc stearate 1.5 parts Dicumyl peroxide 0.75 parts Magnesium oxide 0.23 parts 9
The mixture was kneaded in a heated kneader at 0°C, cooled, and then crushed in a crusher to obtain a dry material that is solid at room temperature.

This material was molded using a JIS K6911 shrinkage mold under molding conditions of 160 kg-/c4.160°C.

Furthermore, in order to investigate the curing property, the curing time was measured using a curelastometer manufactured by Nippon Synthetic Rubber Co., Ltd. under the conditions of 160° C. and 100 ky/crA.

Furthermore, as a simple method, a rice cracker-shaped molded product was molded under the same conditions as in Example 1.

The results are shown in the table below. Example 4 Using resin (4) of Example 1 and resin 0 of Example 2, 20 parts resin (A) 0 parts resin
20 parts calcium carbonate
30 parts silica
5 parts glass fiber 25
Part Zinc stearate 3.0 parts Magnesium oxide 0.68 parts Dicumyl peroxide 1.2 parts Methanol
A mixture of 3 parts was kneaded in a kneader at 80°C, dried and aged at 100°C for 1 hour, cooled and pulverized to obtain a molding material that was solid at room temperature.

Using this material, the curability and shrinkage rate were examined under the same conditions as in Example 1.

The results are shown in the table below.

Comparative Example 1 Instead of resin (4) of Example 1, resin (4) *1 and 2 before the half-esterification reaction with maleic anhydride was used as the resin.
- A styrene-grafted product of polybutadiene glycol was used, and the other conditions were exactly the same as in Example 1, and the mixture was kneaded in a kneader.

The material was putty-like. The results of examining the curability under the same conditions as in Example 1 are shown in the table below.

Based on this result, the molded product for mold shrinkage was molded under the same conditions as in Example 1 except that the molding time was 15 minutes in consideration of slow curing.

The results are shown in the table below.

Comparative Example 2 Without carrying out the styrene grafting reaction of resin (4) of Example 1 as a resin, 1,2-polybutadiene glycol and maleic anhydride were directly half-esterified to obtain a resin with an acid value of 52. A molding material was prepared and evaluated under the same conditions as in Example 1 except for the following.

The results are shown in the table below.

Comparative Example 3 Of Example 1, no magnesium oxide was used, and all others were
The same formulation as in Example 1 was kneaded using a kneader.

The material was putty-like. The evaluation results are shown in the table below.

Comparative Example 4 A molding material was prepared under the same conditions as in Example 3 except that Resin 0 was not used in the formulation of the molding material in Example 3 (25 parts of Resin ■ was used, and all other conditions were the same).

The evaluation is shown in the table below.

Claims (1)

[Claims] A filler is added to the resin component synthesized by half-esterifying a vinyl monomer grafted product of 11,2-polybutadiene glycol and an unsaturated dibasic acid anhydride, and a metal capable of reacting with the terminal carboxyl group in the resin component. A curable molding material comprising a compound and an unsaturated polyester resin.