JPH0867771A - Flame-retardant molding material - Google Patents

Abstract

PURPOSE: To obtain a thermally foamable flame-retardant molding material which contains heat-resistant fibers dispersed throughout its inside and forms a foam layer excellent in flameproof and fire-resistant properties by compounding a specific resin, a specific monomer, heat-resistant fibers, and thermally expansible graphite. CONSTITUTION: This material is prepd. by compounding a free-radical- polymerizable resin (e.g. an unsatd. polyester resin), a free-radical-polymerizable monomer (e.g. methyl methacrylate), heat-resistant fibers (e.g. glass fibers) pref. having lengths of 1-200mm, and thermally expansible graphite. Pref. the compsn. further contains aluminum hydroxide and/or a phosphorus flame retardant (e.g. triphenyl phosphate).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant molding material having excellent anti-fire and fire resistance. In detail, against the flame and heat due to fire etc., the surface to be heated rapidly foams, protects the molding material from flame, high temperature and air, and the foam layer formed here spreads throughout the inside, As a result of being reinforced by the heat resistant fiber, the effect of the foam layer continues and JISA
-1321 Flame-retardant Class 2 advanced flame-retardant property, which does not require special molding conditions and can be applied with ordinary general molding conditions. Excellent sheet-molding compound (hereinafter abbreviated as SMC). ), A bulk molding compound (hereinafter abbreviated as BMC), and the like.

[0002]

2. Description of the Related Art Molding materials such as SMC and BMC are used in bathtub tanks, because of their good moldability and working environment.
It is widely used in septic tanks, automobile parts, etc., but in recent years, it is also widely used in the construction field for various interior materials, roof materials and building materials.

As a method of imparting flame retardancy to a molding material such as SMC or BMC, generally, inorganic powder such as aluminum hydroxide powder, known flame retardant such as halogen, antimony, phosphorus and the like are not used. It is common to mix with a polymerizable resin such as a saturated polyester resin or a polymerizable monomer, and to perform composite molding with a fiber reinforcing material.

However, in this case, for example, JISA-13
There was a problem that high flame retardancy such as 21 flame retardancy class 2 level cannot be expected. Further, the SMC comprising a polymerizable resin containing a known flame retardant component such as halogen or phosphorus in the resin skeleton, or a composition containing the flame retardant component.
Molding materials such as BMC and BMC are also known. However, this molding material has drawbacks such as poor moldability and curability.

Phenol FRP is also well known as a molding material having a high degree of flame retardancy, and has recently been used in railway vehicles and the like. This phenol FRP is JISA
-1321 has excellent flame retardancy that passes Class 2 flame retardancy, but most of them use strong acid at the time of molding, so there are problems such as being difficult to handle and dangerous, and poor workability at the time of molding. There was a problem.

The above-mentioned conventional flame-retardant molding materials represented by SMC and BMC have a high degree of flame retardancy, and very few molding materials require special molding conditions. For example, the conventional techniques using known flame retardants such as aluminum hydroxide described above cannot obtain high flame retardancy.

Further, the conventional technique of the polymerizable resin containing the flame retardant component in the resin skeleton has drawbacks in the workability at the time of molding such that the resin viscosity is usually high and the curing time is long. Furthermore, it has been known for a long time that heat-expandable graphite foams rapidly when exposed to flames and heat, and imparts flame retardancy to the resin. It is also known to sometimes rapidly foam to protect the inside.

However, when the expandable graphite and the thermosetting resin are used, the foam immediately foams upon heating, but the shape retention of the foam layer is insufficient, so that the foam layer collapses or scatters with the wind.
There is a drawback that the effect does not last for a long time.

[0009]

The present invention makes it possible to use ordinary resin blends for molding materials, and while maintaining the properties of conventional molding materials, there is no danger of using strong acids or the like, and JIS It is an object of the present invention to provide a molding material having a high degree of flame retardance that passes the second grade of flame, a fireproof coating property (internal protection effect), and good moldability.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to improve the above-mentioned problems, and as a result, radically polymerizable resins represented by unsaturated polyester resins, heat resistant fibers,
By molding heat-expandable graphite etc. with a predetermined mixing ratio,
We found that a molding material with excellent fireproof coating (internal protection effect), moldability and high flame retardancy can be obtained.
The present invention has been completed.

That is, the present invention is a radically polymerizable resin (A).
A flame-retardant molding material having a heat-foaming property, containing a radical-polymerizable monomer (B), a heat-resistant fiber (C) and a heat-expandable graphite (D), preferably a radical-polymerizable resin (A)
Is one or two selected from the group consisting of unsaturated polyester resin, allyl resin and epoxy vinyl ester resin.
It relates to a flame-retardant molding material which is characterized by being more than one kind.

In the molding material of the present invention, the heat-expandable graphite is first foamed together with the heat-resistant fiber upon heating, the heat-resistant fiber is spread over the entire foam layer, and a strong foam layer is formed. The layer has the characteristic that flame resistance is obtained by blocking the flame, high temperature and air required for combustion from the molding material. Further, by adding a flame retardant, the carbonization of the polymerizable resin and the cured product of the polymerizable monomer is promoted, and higher flame retardancy is obtained.

In the present invention, since the foam layer is reinforced with the heat resistant fiber, there is no collapse or scattering of the foam layer and the blocking effect is maintained for a long time. As a result, high flame retardancy can be realized. Further, by using chemically stable thermally expandable graphite as a foaming agent, molding can be performed under conventional molding conditions without requiring new equipment.

The radical-polymerizable resin (A) used in the present invention may be any resin as long as it has a radical-polymerizable group in the molecule. For example, unsaturated polyester resin, Examples thereof include epoxy vinyl ester-based resins, allyl-based resins, acrylic-based resins, styrene-based resins, divinylbenzene-based resins, alkyd-based resins and the like, which may be used alone or in combination. Among these,
Unsaturated polyester resins, epoxy vinyl ester resins, and allyl resins are preferable from the viewpoints of economical efficiency, moldability, and versatility.

The unsaturated polyester resin is produced by polycondensation of α, β-unsaturated dibasic acid or acid anhydride thereof and aromatic saturated dibasic acid or acid anhydride thereof and glycols. And is produced by optionally using an aliphatic or alicyclic saturated dibasic acid as an acid component.

The unsaturated polyester resin is used by dissolving it in an α, β-unsaturated monomer as a radically polymerizable monomer. In this case, unsaturated polyester resin 30-8
The radical polymerizable monomer is added in an amount of 70 to 20 relative to 0 part by weight.
Used in parts by weight.

Examples of the vinyl ester resin include vinyl-modified unsaturated polyester terminals and vinyl-modified epoxy vinyl ester resins. This vinyl ester resin is used by dissolving it in a radically polymerizable monomer.

Allyl resins generally belong to unsaturated polyester resins in a broad sense, but diethylene glycol bisallyl carbonate and methyl methacrylate (hereinafter referred to as M
(Referred to as MA), a reaction product of diallyl phenyl phosphate and MMA, a reaction product of allyl starch and the like, which are used by dissolving in a radical polymerizable monomer.

Examples of the α, β-unsaturated dibasic acid or its acid anhydride include maleic acid, maleic anhydride, fumaric acid, itanoic acid, citraconic acid, chloromaleic acid, and their esters. Examples of the group saturated dibasic acid or its acid anhydride include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, nitrophthalic acid, tetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, halogenated phthalic anhydride and their esters. Etc., each of which is used alone or as an alicyclic saturated dibasic acid, oxalic acid, molonic acid, sebacic acid, azelaic acid,
There are glutaric acid, hexahydrophthalic anhydride, and their esters, etc., which are used alone or in combination.

As glycols, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-butanediol, 1,
4-butanediol, 2-methylpropane-1,3-diol, neopentyl glycol, triethylene glycol, tetraethylene glycol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, Examples thereof include ethylene glycol carbonate and 2,2-di (4-hydroxypropoxydiphenyl) propane, which may be used alone or in combination, but other oxides such as ethylene oxide and propylene oxide may also be used. A polycondensate such as polyethylene terephthalate can also be used as a part of the glycol and the acid component. Each reaction component is
The compound is not particularly limited as long as it can be polycondensed with the unsaturated polyester.

A resin obtained by reacting a terminal monomer of unsaturated polyester with a reactive monomer having a glycidyl group can also be used. Typical examples of the reactive monomer having a glycidyl group include glycidyl acrylate and glycidyl methacrylate.

The above-mentioned epoxy vinyl ester resin is
More specifically, it is a bisphenol type epoxy resin alone or a mixture of a bisphenol type epoxy resin and a novolac type epoxy resin. This resin is an epoxy vinyl ester obtained by reacting an epoxy resin having an average epoxy equivalent of 250 to 450 with an unsaturated monobasic acid in the presence of an esterification catalyst, and a polymerizable vinyl monomer together with a polymerization inhibitor. It is obtained by dissolving in.

Typical examples of the bisphenol type epoxy resin are epichlorohydrin and bisphenol A or bisphenol F.
Glycidyl ether type epoxy resin having substantially two or more epoxy groups in one molecule obtained by reaction with dimethyl glycidyl ether type epoxy resin obtained by reaction of methyl epichlorohydrin with bisphenol A or bisphenol F Or an epoxy resin obtained from an alkylene oxide adduct of bisphenol A and epichlorohydrin or methylepichlorohydrin.

Typical examples of the novolac type epoxy resin include epoxy resins obtained by reacting phenol novolac or cresol novolac with epichlorohydrin or methylepichlorohydrin.

On the other hand, typical examples of the unsaturated monobasic acid include acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, monomethylmalate, monopropylmalate, monobutylmalate, monopropylmalate and sorbin. Examples include acid or mono (2-ethylhexyl) malate.

These monobasic acids can be used alone or in a mixture of two or more kinds. The reaction between these epoxy resins and the unsaturated monobasic acid is carried out at a temperature of 60 to 140 ° C, preferably 80 to 120 ° C using an esterification catalyst. Examples of the esterification catalyst include triethylamine, N, N-dimethylbenzylamine,
A known catalyst such as a tertiary amine such as N, N-dimethylaniline or diazabicyclooctane; or a known catalyst such as diethylamine hydrochloride, dimethylacetate, or dimethylamine sulfate can be used as it is.

The concentration of the radical-polymerizable monomer used in combination with these is not particularly limited, but
From the viewpoint of workability, impregnation property and performance of the cured product, 5 to 60% by weight is preferable.

Further, in the production of the above-mentioned epoxy vinyl ester resin composition, for the purpose of preventing gelation, adjusting the storage stability or curability of the produced resin,
It is preferable to use a polymerization inhibitor. Typical examples of the above-mentioned polymerization inhibitor used here include hydroquinones such as hydroquinone, pt-butylcatechol or mono-t-butylhydroquinone, hydroquinone monomethyl ether or di-t-butyl-p-cresol. Examples thereof include phenols, quinones such as p-benzoquinone, naphthoquinone and p-toluquinone, and copper salts such as copper naphthenate.

Examples of the radically polymerizable monomer (B) of the present invention include vinyl monomers or vinyl oligomers which are crosslinkable with the above radically polymerizable resins such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, methylmethacrylate and divinylbenzene. Can be mentioned. These can be used alone or in combination. Of these, styrene and MMA are common from the viewpoints of compatibility with resins, economy, moldability, versatility, and the like.

The heat-resistant fiber (C) of the present invention is not particularly limited as long as it has excellent heat resistance and is suitable for the present application. For example, glass fiber produced from various kinds of glass, rock wool, carbon fiber. Inorganic fibers such as graphite fibers and sild fibers, and heat resistant organic fibers represented by phenol resin fibers and the like can be used, and these can be used alone or in combination. Heat resistant fiber is 200 ℃,
It is preferable that the change in shape at 300 ° C. is slight and the reinforcing effect of the foam layer can be maintained.

The fiber length of the heat resistant fiber is slightly different depending on the kind of the heat resistant fiber, but is generally 1 to 200 m.
m, preferably 5 to 100 mm. Ie 1 mm
If it is less than the above range, the reinforcing effect of the foamed layer after heating is not sufficiently exhibited, and as a result, the strength of the foamed layer is weak, which is not preferable. Also,
If it exceeds 200 mm, the heat-resistant fibers do not integrally foam at the time of foaming, so that the heat-resistant fibers are unevenly distributed in the lower part of the foam layer, the reinforcing effect of the foam layer is not sufficiently expressed, and as a result, the strength of the foam layer becomes weak, None of them achieves the intended effect of the present invention.

The shape of the heat resistant fiber such as width and thickness is such that the heat resistant fiber is integrally foamed at the time of heat foaming, and as a result, the heat resistant fiber is present throughout the foamed layer. Although not particularly limited, the width is usually 0.1 to 40
mm, preferably 0.5 to 3 mm. The thickness is 0.01 to 2 mm, preferably 0.02 to 1 mm.

From the point of view of the present invention, it is important that each heat-resistant fiber can move without being physically constrained during heat-foaming, and from this point of view, it can be matted with a woven fabric, heat-resistant binder or the like. It is not preferable to use the above-mentioned materials (glass mat, etc.) or those in which the individual fibers are bound by other methods.

The amount of the heat-resistant fiber added is not particularly limited as long as it achieves the object of the present invention, but is usually 5 to 70% by weight based on the total weight of the molding material containing the heat-resistant fiber. %, Preferably 10 to 40% by weight.

Any of the heat-expandable graphite (D) of the present invention can be used as long as it is in accordance with the gist of the present invention. Generally, the heat-expandable graphite is an interlayer of natural scaly graphite. It is a product in which an acid component such as water or sulfuric acid is inserted. Generally, graphite is a hexagonal crystal in which flat six-membered ring polymer layers are superposed on each other, and the bonding force between the layers is very weak. Therefore,
Various heteroatoms can be inserted between the layers of the six-membered ring polymerization surface of this graphite to generate a graphite intercalation compound. Some of them are activated by heating to generate fluid pressure, and The layer expands and expands.

Any of phosphoric acid-treated or alkali metal salt-treated or resin-coated graphite or the like may be used for the purpose of preventing corrosion due to the acid component contained in the thermally expandable graphite. is there. The particle size of thermally expandable graphite is usually 2
It is 0 to 100 mesh, and preferably 40 to 80 mesh, but there is no particular limitation as long as it realizes the present invention,
Either can be used.

The content of this thermally expandable graphite is 5 to 100% by weight, preferably 5 to 40% by weight, based on the radical polymerizable resin. Further, various known flame retardants can be added for the purpose of improving flame retardancy.

Although the thermally expansive graphite has a strong acid such as sulfuric acid between the layers, the pH of the product is often 4 to 7, and it is said that no acidic component is generated from the layers. The resin used is generally an unsaturated polyester resin or vinyl ester resin with excellent acid resistance, and it is expected that even if the acidic component flows out, it will show excellent resistance compared to other resins. It

As the flame retardant of the present invention, any flame retardant which can meet the purpose of the present invention can be used, but a phosphorus-based flame retardant is preferable in view of the toxicity of the gas generated during combustion. As the phosphorus-based flame retardant, for example, red phosphorus, triphenyl phosphate, dimethyl methyl phosphate, tricresyl phosphate or the like can be used alone or in combination. Further, a flame-retardant having poor miscibility with a radical-polymerizable resin such as ammonium phosphate or a radical-polymerizable monomer, which is microencapsulated with an epoxy resin or the like, can naturally be used.
Other known flame retardants such as boron and antimony can also be used together.

The aluminum hydroxide of the present invention can be used as a flame-retardant filler as long as it achieves the object of the present invention, but the particle size thereof is usually from 40 to 600.
The mesh is preferably 60-400 mesh.

The amount of aluminum hydroxide added is 1 to 500% by weight, preferably 5 to 300% by weight, based on the resin. In this way, the molding material of the present invention can be obtained. If necessary, a curing agent, a curing accelerator, a low-shrinking agent, a filler and the like are added to the molding material of the present invention, and the addition of a curing agent and a curing accelerator is particularly preferable in terms of accelerating the curing.

Examples of the curing agent include organic peroxides. Specific examples of the organic peroxide include diacyl peroxide-based, peroxyester-based, hydroperoxide-based, peroxyketal-based, alkylperester-based, and percarbonate-based ones. When a curing agent is used, it is appropriately selected and used according to the kneading conditions, aging conditions and the like.

The amount of the curing agent added is a commonly used amount, and preferably the radical polymerizable resin composition 100.
It is 0.04 to 4 parts by weight with respect to parts by weight. The above curing agents may be used in combination.

The curing accelerator is a substance having a function of decomposing the organic peroxide of the curing agent by a redox reaction and facilitating generation of active radicals. For example, cobalt-based, vanadium-based manganese-based metal soaps and the like. Inorganic thickeners such as alkaline earth metal oxides or hydroxides such as amides, tertiary amines, quaternary ammonium salts and mercaptans, as well as tolylene diisocyanate (TDI), 4,4 '
Examples thereof include polyisocyanate type organic thickeners such as diphenylmethane diisocyanate (MDI) and crude MDI. These can be used alone or in combination.

The amount of the above-mentioned curing accelerator used is appropriately determined depending on the viscosity of the radical-polymerizable resin composition after thickening, and the addition amount thereof is usually 0.05 per 100 parts by weight of the radical-polymerizable resin composition. -20 parts by weight, preferably 0.1-
10 parts by weight is good.

Examples of the low shrinkage agent include polystyrene,
Examples thereof include thermoplastic resins such as polyethylene, polyacrylate, polyvinyl acetate, and saturated polyester, which may be used alone or in combination.

Examples of the filler include calcium carbonate,
Kaolin, barium sulfate, etc. may be mentioned, but hollow ceramics, hollow glass or hollow graphite spheres may also be used in order to reduce the density of the final molded product.

In addition to the above additives, internal release agents, bone agents, pigments, colorants, dyes and the like can be used in the same manner as in the past. Examples of the internal release agent include zinc stearate,
Examples thereof include calcium stearate.

The amounts of these additives used may be those conventionally used. The molding material of the present invention obtained by mixing the above raw materials is molded by compression molding, transfer molding, injection molding or the like at a temperature below the foaming initiation temperature of the heat-expandable graphite to obtain a wide range of flame-retardant FRP molded products. be able to.

[0050]

The present invention will be described in more detail with reference to the following examples, in which "part" and "%" are based on weight.

Examples 1 to 10 and Comparative Examples 1 to 11 Under the compounding conditions shown in the table, SMC and BMC are formed, and equipment and molding conditions generally used for molding ordinary SMC and BMC, that is, 130 ° C. are set. Using a mold with a compression molding machine, a flat plate having a thickness of about 3 mm was prepared under the molding conditions of 70 kg / cm ² and 5 minutes. The produced flat plate was cut into 22 cm square, and a JIS-A1321 flame-retardant grade 2 surface test was performed to evaluate the flame-retardant property.

As comparative examples, Comparative Examples 1 to 9 shown in Table 2
In addition, commercially available flame-retardant SMC molded products (polyester resin) and phenol FRP molded products were similarly subjected to JIS-A1321 flame-retardant class 2 surface test as Comparative Examples 10 and 11.

[0053]

[Table 1]

* 1; Unsaturated polyester resin * 2; Vinyl ester resin * 3; Halogen-containing flame-retardant resin * 4; Polystyrene-based non-shrinking agent * 5; Commercially available glass fiber cut into 1 inch fiber length * 6; Latent curing agent for saturated polyester resin (thermosetting) (made by NOF Corporation)

[0055]

[Table 2]

* 1; Commercial glass fiber cut into a fiber length of 1 inch * 2; Commercial glass fiber cut into a fiber length of 0.5 mm * 3; Commercial glass fiber cut into a fiber length of 250 mm Results of flame retardant test Shows Tables 3 and 4, all of the molding materials of the present invention exhibit high flame retardancy, and Comparative Examples 1 to 9 based on a polymerizable resin and a commercially available general flame-retardant unsaturated polyester resin SMC. Resulted in much smoke and inferior flame retardancy. Further, although the phenol FRP has good flame retardancy, the workability during molding is remarkably poor as compared with the polyester resin SMC.

[0057]

[Table 3]

[0058]

[Table 4]

[0059]

The flame-retardant molding material of the present invention has the following excellent effects. (1) The molding material of the present invention rapidly foams when heated to form a foamed layer in which reinforcing fibers are spread inside, and a foam layer reinforced with this refractory fiber which is difficult to scatter, flame, high temperature or As a result of blocking and protecting the inside from the air and continuing the effect, a high level of flame retardancy of JIS A1321 flame retardancy class 2 level is obtained. (2) It can be molded under the same molding conditions as ordinary SMC and BMC.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08K 5/521 KCB 7/02 KCJ C08L 57/04 LMK 67/06 MSC

Claims (7)

[Claims] 1. A flame-retardant molding material having a heat-foaming property, which comprises a radical-polymerizable resin (A), a radical-polymerizable monomer (B), a heat-resistant fiber (C) and a heat-expandable graphite (D). . 2. The molding according to claim 1, wherein the radically polymerizable resin (A) is one or more selected from the group consisting of unsaturated polyester resins, allyl resins and epoxy vinyl ester resins. material. 3. The heat resistant fiber (C) has a fiber length of 1 to 200 mm.
The molding material according to claim 1 or 2, wherein 4. The molding material according to claim 1, further comprising aluminum hydroxide. 5. The molding material according to claim 1, further comprising a phosphorus-based flame retardant. 6. The molding material according to claim 5, wherein the phosphorus-based flame retardant is triphenyl phosphate and / or tricresyl phosphate. 7. The molding material according to claim 1, wherein the thermally expandable graphite (D) is used in an amount of 5 to 100% by weight based on the radically polymerizable resin.