JPH04153267A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition which is lightweight and improved in mechanical strength by incorporating cross-linked hollow polymer particles into a thermosetting resin. CONSTITUTION:A thermosetting resin composition made of 10-99wt.% thermosetting resin (e.g. a phenol resin or an epoxy resin) and 1-90wt.% cross-linked hollow polymer particles. The polymer particles can be prepared by various methods, but most desirably they should be prepared by the two-stage cross- linking method in which cross-linked polymer particles are used as seeds, and a polymer having a different compatibility is polymerized and cross-linked on these seeds. By using the cross-linked hollow polymer particles of the invention, it is possible to reduce the weight of a thermosetting resin composition with no or minimized reduction in mechanical strength.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a thermosetting resin composition that is lightweight and has excellent mechanical strength, which is made by blending crosslinked hollow polymer particles.

[Prior Art] Generally, thermosetting resins, especially phenolic resins and epoxy resins, have been widely used for various molding materials and adhesives since ancient times due to their excellent adhesive properties, insulation properties, and heat resistance.

Even with the rapid growth of the automobile industry and electrical/electronic industry in recent years, demand for it is increasing mainly for use in various parts by taking advantage of its characteristics.

One of the things that has been attracting attention recently is weight reduction. For example, in automobiles that use many of these molded products, reducing the weight of automobiles in order to improve their performance and fuel efficiency has become a major technical issue. In addition, weight reduction is attracting attention in other applications as well, for reasons such as ease of transportation and improved performance.

Conventional methods for reducing the weight of molded products include the following.

(1) A method to reduce the thickness of the molded product and avoid excessive quality.

(2) A method of foaming the inside of a molded product by using a molding material containing a foaming agent.

(3) A method of incorporating hollow glass spheres into a molded product using a molding material containing fine hollow glass spheres.

Method (1) is the easiest method to implement and has already been implemented to its limits.

Method (2) is the most effective method for weight reduction, but foaming significantly reduces the mechanical strength of the molded product, and it is not recommended as a method for weight reduction of molded products that require mechanical strength.
It cannot be implemented.

In method (3), the mechanical strength is significantly reduced and the hollow glass bulbs are broken by the mixing or molding exhaust, so that weight reduction cannot be expected.

Therefore, in the conventional technology, reducing the weight of thermosetting resins has had a major effect in that the mechanical strength is significantly reduced.

[Problems to be Solved by the Invention] As a result of various studies on thermosetting resins that are lightweight and have excellent mechanical strength, it has been found that thermosetting resin compositions containing crosslinked hollow polymer particles have lower performance compared to conventional methods. The present invention was achieved by discovering that it is possible to reduce the weight without reducing the mechanical strength or minimizing the decrease.

Means for Solving the Problem] The present invention provides a thermosetting resin composition characterized by comprising 10 to 99% by weight of a thermosetting resin and 1 to 90% by weight of crosslinked hollow polymer particles. be.

The present invention will be described in detail below.

Examples of the thermosetting resin of the present invention include phenol resins, epoxy resins, melamine resins, unsaturated polyester resins, and alkyd resins, but phenol resins, epoxy resins, and unsaturated polyester resins are preferred for ease of mixing. More preferred are phenol resins and epoxy resins.

The crosslinked hollow polymer particles used in the present invention can be produced in a variety of ways. That is, (I) a method in which a blowing agent is contained in crosslinked polymer particles and the blowing agent is then foamed.

(n) A method in which a volatile substance such as butane is encapsulated in a crosslinked polymer, and the volatile substance is then gasified and swollen.

(III) A method in which a crosslinked polymer is melted and a jet of gas such as air is blown thereto to seal in air bubbles.

(TV) A method of infiltrating an alkali-swellable substance into the inside of crosslinked polymer particles to swell the alkali-swellable substance.

(V) A method of preparing a w10/w type monomer emulsion and conducting polymerization.

(VI) A method in which monomers are polymerized in a solution in which a pigment is suspended in an unsaturated polyester solution.

(■) A two-step crosslinking method in which crosslinked polymer particles are used as seeds and polymers with different compatibility are polymerized and crosslinked onto the seeds.

(■) Method of manufacturing by polymerization shrinkage of polymer (IX)
Method 3 includes spray-drying crosslinked polymer particles.
A preferred method is method (2), and the most preferred embodiment of method (2) is a method in which crosslinking monomer (a) 1 to 50
Hydrophilic monomer (b) (hereinafter referred to as "hydrophilic monomer (b)") consisting of 1 to 40% by weight of unsaturated carboxylic acid and/or 5 to 99% by weight of other wood-philic monomers (hereinafter referred to as "hydrophilic monomer (b)") 1 to 99% by weight % by weight, and the crosslinking monomer (a
) or other polymerizable monomer (C) that can be copolymerized with the hydrophilic monomer (b) (hereinafter referred to as "other polymerizable monomer (C)") 100 weight% of a polymerizable monomer component consisting of 0 to 85% by weight 1 part by weight of a different polymer having a composition different from that of the polymer of the polymerizable monomer component in water, and then polymerizing the polymerizable monomer component. (Japanese Unexamined Patent Publication No. 61-127336). Furthermore, the crosslinked hollow polymer particles can be produced as a sea polymer by seed polymerizing at least one selected from crosslinkable monomers, hydrophilic monomers, and polymerizable monomers (Japanese Unexamined Patent Publication No. 2-140271, Same 2
-140272).

Examples of the crosslinkable monomer (a) include divinyl-based monomers or trivinyl-based monomers such as divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate. Divinylbenzene, ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate are particularly preferred.

As the wood-philic monomer (b), vinylpyridine, glycidyl acrylate, glycidyl methacrylate, methyl acrylate, methyl methacrylate, acrylonitrile, acrylamide, methacrylamide, N-
Methylol acrylamide, N-methylolmethacrylamide, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, sodium styrene sulfonate, vinyl acetate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. Examples include vinyl monomers. Among these, methacrylic acid, itaconic acid, and acrylic acid are preferred.

The other polymerizable monomer (C) is not particularly limited as long as it has radical polymerizability, and includes styrene,
Aromatic vinyl monomers such as α-methylstyrene, p-methylstyrene, halogenated styrene, vinyl esters such as vinyl propionate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethyl ethylenically unsaturated carboxylic acid alkyl esters such as hexyl methacrylate, lauryl acrylate, and lauryl methacrylate;
Examples include maleimide compounds such as phenylmaleimide and cyclohexylmaleimide, conjugated diolefins such as butadiene and isoprene, and styrene is particularly preferred. The polymer obtained by polymerizing is required to be of a different type or composition and to be easily soluble in the polymerizable monomer.

Examples of such different polymers include polystyrene, carboxy-modified polystyrene, carboxy-modified styrene-butadiene copolymer, styrene-butadiene copolymer, styrene acrylic ester copolymer, styrene methacrylic ester copolymer, acrylic ester copolymer, methacrylic ester copolymer, and carboxy-modified styrene-butadiene copolymer. Examples include styrene acrylic ester copolymer, carboxy-modified styrene methacrylic ester copolymer, carboxy-modified acrylic ester copolymer, and carboxy-modified methacrylic ester copolymer. Among these, polystyrene or a styrene copolymer containing 50% by weight or more of a styrene component is particularly preferred.

The degree of crosslinking of the crosslinked hollow polymer particles of the present invention refers to three-dimensional crosslinking to such an extent that the shape of the particles is maintained at the curing temperature of the thermosetting resin in which the crosslinked hollow polymer particles are blended.

The glass transition temperature (T
g) is preferably 100°C or higher, more preferably 1
The temperature is 20-200°C. When Tg is within the above range, even better effects aimed at by the present invention can be obtained.

The average outer diameter of the crosslinked hollow polymer particles of the present invention is preferably 5 microns or less, more preferably 1 micron or less, particularly preferably 0.1 to 1 micron. It is preferable to use particles in this range because the mechanical strength is even better.

Considering the balance between weight reduction and mechanical strength, the inner diameter of the crosslinked hollow polymer particles of the present invention is 0.2 to 0.2 to the outer diameter.
Preferably, it is in the range of 0.9 times.

The composition ratio of the thermosetting resin and crosslinked hollow polymer particles of the present invention is 10 to 99% by weight of the thermosetting resin,
Preferably 30 to 95% by weight, more preferably 60 to 95% by weight
95% by weight, while the crosslinked hollow polymer particles
It is 90% by weight, preferably 5 to 70% by weight, more preferably 5 to 40% by weight. 10% by weight thermosetting resin
If the content of the crosslinked hollow polymer particles exceeds 90% by weight, the mechanical strength and excellent performance of the thermosetting resin will deteriorate, which is undesirable. 1% by weight of crosslinked hollow polymer particles
(less than), the desired weight reduction cannot be achieved.

In the present invention, it is important to use crosslinked hollow polymer particles, and the purpose of the present invention can be achieved by using crosslinked hollow polymer particles.

To specifically demonstrate the desired effect of the present invention, when the specific gravity is the same through weight reduction, the material produced by the weight reduction method of the present invention has superior mechanical strength compared to the conventional weight reduction method. That's true.

The method of mixing the thermosetting resin and crosslinked hollow polymer particles is as follows:
Preferably, the method involves heating and mixing.

For mixing, a closed mixer such as a Banbury mixer, a roll, an extruder, etc. can be used depending on the purpose.

In addition, the composition of the present invention may contain anti-aging agents, stabilizers, plasticizers, softeners, various inorganic or organic fillers, as necessary.
Reinforcing agents, crosslinking agents, glass fibers, metal fibers, carbon fibers, etc. can be used in combination.

The composition of the present invention can be applied to molding methods described in "Introduction to Plastics (published by Kogyo Research Association)", pages 80 and 81, such as the hand lay-flop method, the spray stub method, the FW method, and the SM method.
The desired molded product can be obtained using the C method, continuous pultrusion method, 8MC method, premix method, preform method, FRP method, etc.

The composition of the present invention is suitable for electrical/electronic parts, automobiles, coatings mainly for building materials, electrical/electronic parts, vehicle parts,
It can be widely used in building materials, casting agents, molding materials, adhesives, paints, etc.

Next, the present invention will be explained in more detail with reference to Examples.

In the examples, unless otherwise specified, parts and % indicate parts by weight and % by weight.

(1) Crosslinked hollow polymer particles A> 70 parts of styrene, 27 parts of butadiene, 3 parts of itaconic acid and 12 parts of t-dodecyl mercaptan, 200 parts of water, 0.5 part of sodium lauryl sulfate and potassium persulfate While stirring an aqueous solution containing 1.0 part of
Polymer particles were obtained by polymerization for 8 hours. This polymer particle has an average particle size of 0.24 μm and 6% of toluene-insoluble bone.
, the number average molecular weight by GPC is 5.000. The ratio of weight average molecular weight to number average molecular weight, Mw/Mn, was 2.6.

Next, using this polymer particle as a seed polymer particle,
This polymer particle was mixed with 10 parts of solids and 0.0 parts of polyoxyethylene nonylphenyl ether. 1 part, 0.4 parts of sodium lauryl sulfate, and 0.5 parts of potassium persulfate to 9 parts of water.
00 parts. When a mixture of 30 parts of methyl methacrylate, 50 parts of divinylhensen, 20 parts of α-methylstyrene, and 20 parts of toluene was added to this and polymerized at 70°C for 5 hours, the polymerization yield was 98% and toluene was contained inside the particles. A dispersion of capsule particles was obtained.

After this dispersion was subjected to a steam strip treatment, the polymer particles were observed using a transmission electron microscope, and the polymer particles were transparent at the center and were completely spherical crosslinked hollow polymer particles. The outer diameter of this particle is 0
, 44μm1 inner diameter 0.3μm, Tg 150℃ or more,
Specific gravity is 0. It was 72.

Crosslinked hollow polymer particles B> The amount of methyl methacrylate used in crosslinked hollow polymer particles A was 50 parts, and the amount of divinylbenzene was 30 parts.
The outer diameter is 0.72μm in the same way as A except that
Crosslinked hollow polymer particles with an inner diameter of 0.48 μm, a Tg of 150° C. or more, and a specific gravity of 0.73 were obtained.

<Glass hollow beads> Manufactured by Asahi Glass Average particle size 56 μm Density 0.36 g/crtl Example 1 Using the above crosslinked hollow polymer particles A, a thermosetting resin composition (epoxy resin composition) was prepared according to the following procedure. Obtained.

Cresol nophorac type epoxy resin (epoxy equivalent: 200) 100 parts by weight Phenol resin (novolac type) 50 parts by weight Curing agent (2-methylimidazole) 5 parts by weight Crosslinked hollow polymer particles A 37.5 parts by weight These were mixed in a closed mixer. Samples for physical property evaluation were prepared by thoroughly kneading the mixture at about 80° C., performing plus molding at 160° C., and processing the obtained molded plate with a milling machine. The evaluation results are shown in Table-1.

Example 2 This is an example in which crosslinked polymer particles B were used in place of the crosslinked hollow polymer particles A of Example 1. The evaluation results are shown in Table-1.

Comparative example 1 This is an example in which crosslinked hollow polymer particles are not used in Example 1.

The evaluation results are shown in Table-1.

Comparative Example 2 This is an example in which glass hollow beads were used instead of the crosslinked hollow polymer particles A of Example 1. The evaluation results are shown in Table-1.

Example 3 Using (A) used in Example 1, a phenol resin composition was obtained in the following procedure.

Phenol resin (novolac type) 100 parts by weight Hexamethylenetetramine 10 parts by weight Crosslinked hollow polymer particles A 25 parts by weight According to the above recipe, kneaded with an electric heated roll at 130°C for 5 minutes and then crushed.
By press molding at 160℃ for 10 minutes, the thickness of 4
A molded plate of M was obtained. This was processed using a milling machine according to JIS K-6911 to prepare a test piece. The test results are summarized in Table-1.

Example 4 This is an example in which crosslinked hollow polymer particles B were used in place of crosslinked hollow polymer particles A in Example 3. The evaluation results are shown in Table-1.

Example 5 This is an example in which the amount of crosslinked hollow polymer particles A used in Example 3 was changed from 25 parts to 66.6 parts. The evaluation results are shown in Table-1.

Comparative Example 3 This is an example in which the crosslinked hollow polymer particles A of Example 3 were not used. The evaluation results are shown in Table-1.

Comparative Example 4 This is an example in which 25 parts of glass hollow beads were used in place of the crosslinked hollow polymer particles A of Example 3. The evaluation results are shown in Table-1.

Comparative Example 5 This is an example in which 66.6 parts of glass hollow beads were used in place of the crosslinked hollow polymer particles A of Example 3.

The evaluation results are shown in Table-1.

Regarding Example 1.2 and Comparative Example 1.2, the crosslinked hollow polymer particles of the present invention were blended from Comparative Example 1 without the addition of crosslinked hollow polymer particles, Comparative Example 2 with the addition of glass hollow beads, and Example 1.2. It can be seen that the weight of the thermosetting resin composition is reduced without impairing the mechanical strength of the thermosetting resin.

Regarding Example 3.4.5 and Comparative Example 3.4.5 From Comparative Example 3 without the addition of crosslinked hollow polymer particles and Comparative Example 4.5 and Example 3.4.5 with the addition of glass hollow beads, the present invention The thermosetting resin composition blended with crosslinked hollow polymer particles can be made lighter without impairing the mechanical strength of the thermosetting resin. The thermosetting resin compositions of Comparative Examples 2.4.5 were not light weighted or were hollow or destroyed during mixing or molding.

Below are blank spaces [Effects of the invention] Are there any known conventional methods for reducing the weight of thermosetting resins, such as foaming using a foaming agent or adding glass hollow beads? This significantly lowers the mechanical strength of the material, making it completely impractical for applications that require high mechanical strength.

However, the method of adding the crosslinked hollow polymer particles of the present invention makes it possible to reduce the weight of the thermosetting resin without impairing the mechanical strength or minimizing the decrease.

Such excellent effects were achieved for the first time using crosslinked hollow polymer particles.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] (1) A thermosetting resin composition comprising 10 to 99% by weight of a thermosetting resin and 1 to 90% by weight of crosslinked hollow polymer particles.