JPS5971338A - Thermoplastic resin foam - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin foam having excellent flame-retarddance, and resistant to the bleeding out of the formed sheet during the long-term storage, by using a thermoplastic resin compounded with a crosslinked bisphenol A-type brominated epoxy resin product containing a specific amount of bromine, as a main component. CONSTITUTION:A crosslinked bisphenol A-type brominated epoxy resin obtained by the three-dimensional crosslinking of a bisphenol A-type brominated epoxy resin (e.g. tetrabromobisphenol A diglycidyl ether) with a curing agent (e.g. ethylenediamine) is added to a thermoplastic resin (e.g. a polyolefin resin). The amount of the crosslinked resin is selected to give a foamed article having a bromine content of >=2.0wt%. The mixture is further compounded with a foaming agent (e.g. azodicarbonamide) and if necessary, flame retardant, flame retarding assistant, inorganic filler, heat-stabilizer, etc., kneaded, formed in the form of a sheet, crosslinked, and foamed to obtain the objective thermoplastic resin foam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin foam having excellent flame retardant properties.

In general, thermal ITrffi curved resin foams having one cellular cotton cell are widely used as heat insulating materials, heat retaining materials, cushioning materials, etc. because they are inexpensive, lightweight, and have excellent heat insulation, water resistance, and sound absorption and insulation properties.

In recent years, thermoplastic resin foams have come to be used in the field of building materials, etc., taking advantage of their excellent fF notes, but thermoplastic resin foams have a drawback of being easily twisted, which greatly limits their uses.

For this reason, various flame-retardant thermoplastic resin foams have been proposed. Among them, it is known that a combination of a halogenated aromatic compound such as hexabromobenzene or decabromodiphenyl ether with a flame retardant aid such as antimony trioxide exhibits excellent twist resistance and has been put into practical use.

However, even though such flame-retardant thermoplastic resin foams are available, they still have the following drawbacks.

In other words, flame-retardant thermoplastics are inferior! 11. Resin foam softens and melts when it burns, and the burning part drips, so while the combustion of the foam itself can be suppressed, it has the disadvantage that the dripping burning part can spread the fire to other materials.

The inventors of the present invention have conducted intensive studies to develop a flame-retardant thermoplastic resin foam that does not cause such a drip phenomenon.
First, we discovered that by incorporating a bisphenol A-based brominated epoxy resin into a foamed Netomachi plastic resin, it was possible to obtain a foam that was superior in retaining the cedar shape and being difficult to twist when burned.
I proposed it to Ding. However, even with this invention, bisphenol A
There was a drawback that the brominated epoxy resin gradually bleed out to the surface of the sheet.

The object of the present invention is to provide a hot molded resin foam that does not bleed out even when a molded sheet or the like is stored at room temperature for a long period of time, prevents dripping during combustion, and has excellent twist resistance. That is.

The object of the present invention is to provide a foam mainly composed of Netsumachi plastic casting resin mixed with bisphenol A-based odor-accumulating epoxy/resin 41fR#I, which contains bisphenol-A-based odor-accumulating epoxy resin cross-linked. This is achieved by Netsumachi Plastic Injection Resin/1!11 bottles containing 2.0% by weight or more of bromine based on the foam.

The thermal 0T heavy resin according to 8 of the present invention refers to polyolefin resin, polyether resin such as polyacetal, ABS
Well-known resins such as polyester resins and polyamide resins are shown, but polyolefin resins are also preferred for the first part.

Specifically, the polyolefin resins include homopolymers of α-olefins such as 16-olefin, propylene, butene-1,4-methylpentene-1, copolymers thereof, and monomers thereof. A monomer mixture containing one or more of other monomers capable of copolymerizing with, for example, vinyl acetate, vinyl compounds such as acrylic esters, and conjugated diene compounds such as butadiene and isoprene. The copolymerization obtained from the above-mentioned polymers includes -s and thermoplastic resins whose main components are essentially the above-mentioned polymers.

In the present invention, the crosslinked bispheno-/L'A-based odor-based epoxy resin refers to a mixture of two or more bisphenol A-based brominated epoxy resins or those with different bromine contents, or brominated epoxy resins thereof. It is an insoluble and infusible product obtained by three-dimensionally crosslinking an epoxy resin mixed with a known epoxy resin using a conventionally known curing agent for epoxy resins.

A representative example of the bisphenol A-based brominated epoxy resin used by Kakanahashi is a brominated epoxy resin (formula 2) mainly consisting of tetrabromobisphenol A diglycidyl ether 71/(formula 1)g.

Usually, most of these bisphenol A-based brominated epoxy resins have an epoxy equivalent of 200 to 1000 and a molecular weight of 4.
00-4000. As a specific commercially available product, Sumieboki 7″EBB-340,40 manufactured by Sumitomo Chemical Co., Ltd.
0,500,700'P manufactured by Dow Chemical Company, DER-
511, 542, etc., and further manufactured by Shell Chemical Co., Ltd., 1045-
There are B-80, DX-248-E-80, etc. Specific examples of curing agents necessary for three-dimensional crosslinking of brominated epoxy resins include ethylenediamine, diethylenetriamine, triethylenetetramine, metaphenylenediamine, and 4.
Amine catalysts such as 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, boron trifluoride monoetheramine complex, acid anhydride catalysts such as maleic anhydride, phthalic anhydride, methylhimic anhydride, and other dicyandiamides. , imidazole, polyamide resin, etc.

The thermoplastic resin foam of the present invention is mainly composed of a thermoplastic resin mixed with a bisphenol A-based brominated epoxy resin crosslinked product, and the brominated epoxy resin crosslinked product is contained in the foam at a bromine content of 2.0% by weight. Although it contains the above, the bubbles are composed of closed cells, and Natsumachi Sosatsu resin is crosslinked and S
The expanded shape is preferably sheet-like.

In the present invention, as mentioned above, the essence is to contain the bisphenol A-based brominated epoxy resin crosslinked product in the foam at a bromine content of 2% by weight or more. , lack of shape retention due to carbonization,
This is not preferable because it causes dripping. When the content is 2% by weight or more, carbonization of the base thermoplastic resin is promoted during external combustion and firing, and the drip phenomenon does not occur even when the shape, occlusion and retention are increased. Preferably, by containing the crosslinked bisphenol A-based brominated epoxy resin at a bromine content of 4% by weight or more, shape retention during combustion can be more stably obtained, and self-extinguishing properties can be obtained.

Note that the term "drip" as used herein refers to a state in which a burning part melts and drips when a foam is held horizontally in a combustion test. Father, does shape j sweet retention mean that the burning part softens? A state in which horizontal deformation is difficult to occur.

In general, epoxy resins with a high bromine content (bromine content 4
6 to 50% by weight) of the crosslinked product, the foam contains 5% by weight.
It is possible to obtain sufficient shape retention and high degree of twist resistance by adding up to 10% by weight. In the case of a crosslinked epoxy resin with a low bromine content (bromine content 18 to 25% by weight), the same effect can be obtained by increasing the amount added to the foam, 15 to 30% by weight. It will be done.

The effect of preventing the drip phenomenon and imparting a high degree of twist resistance increases as the amount of the crosslinked bisphenol A-based brominated epoxy resin increases, but if it is too loose, extrudability, sheet formability, Furthermore, problems arise in the foam manufacturing process and the quality of the foam, such as foamability, so the upper limit of the amount of crosslinked bisphenol A-based brominated epoxy resin added is usually 70% by weight based on the foam. Preferably limited.

The foam of the present invention may optionally contain flame retardant aids such as antimony trioxide and other flame retardants such as herogen-containing compounds and phosphorus compounds. Calcium, silica, talc, aluminum silicate, baricum sulfate, titanium oxide, etc., other inert inorganic compound fillers, heat stabilizers, anti-emetic agents, plasticizers, pigments, etc. can be used together. In this case, the amount of inorganic filler added, even if used in combination with the bisphenol A-based brominated epoxy resin crosslinked product, will not cause any problems in all processes such as extrusion pouring, sheet molding pouring, foam pouring, and foaming. The total amount added is limited to the range that can maintain the performance as 70! It should be kept below i%.

Next, a method for producing a thermoplastic resin foam according to the present invention will be explained.

First, the bisphenol A-based brominated epoxy resin crosslinked product is
It is preferably manufactured by a method in which a brominated epoxy resin prepolymer is prepolymerized by adding a curing agent in advance and is further treated at a high temperature to three-dimensionally crosslink it. In order to uniformly disperse the resin into the resin shell, it is preferable to use a powder coating at the end.

A known method can be used for preborifing the piphenol A-based brominated epoxy resin. Since the pre-coating conditions are determined by the curing agent used, it is desirable to set the conditions according to each curing agent. Axiom's hardening agents are used as the hardening agent, but among them, polymerization degree L
6 is gradual and the desired result is better this time. Boron trifluoride monoethylamine complex, which is a hardening agent, is used in 1! ! ! It is preferable to use Brominated epoxy resin such as BSB-4
00 and when using boron trifluoride monoetheramine complex as a curing agent, the amount added l″1EsE-400
It may be used in an amount of 3 to 5 parts by weight per 100 parts of 100 parts by weight, and a prepolymer can be obtained by reacting the two with stirring for 1 to 6 hours using ioo'c. The purpose of this prepolymerization is to easily reduce the OI'η of three-dimensionalization through subsequent heat treatment, so the degree of polymerization of the prepolymer should be at least as long as a curing agent is incorporated into the polymer shell, and at most There is no particular restriction as long as it does not cause gelation.

When a prepolymer of a bisphenol A-based brominated Evoquin resin is heat-treated to form a three-dimensional crosslinked product, the bulk prepolymer heat-treated to form a chestnut material is extremely hard and difficult to form into a uniform, fine powder. However, the powdered prepolymer is heat-treated at 150°C (11°C).
The crosslinked product obtained after 5 minutes or 180°C can be easily powdered. Furthermore, if the prepolymer powder is mixed with other inorganic fillers and heat treated, a brominated epoxy resin crosslinked powder can be obtained even more easily.

The three-dimensional crosslinked product thus powdered is uniformly mixed and dispersed in a thermoplastic resin together with a blowing agent and other additives. As the blowing agent, a known blowing agent such as azodicarbonamide may be used.

As described above, the amount of the crosslinked bisphenol A-based brominated epoxy resin added is such that the bromine content is 2% by weight or more based on the resulting foam. Of the various additives, only about 50% by weight of the blowing agent disappears as volatile gas.

Therefore, the amount of the brominated epoxy resin crosslinked material to be added to the foam must be determined by taking into account the loss of the above-mentioned enveloping agent.

The foam of the present invention is preferably one that has been crosslinked, and when this crosslinking treatment is carried out using a chemical crosslinking agent, it is necessary to add the chemical crosslinking agent in advance. Examples of the chemical crosslinking agent include organic peroxides, such as dicumyl peroxide, ditertiary butyl peroxide, 1,3-bis(tertiarypterperoxyisobrobyl)benzene, and 4. 4-ditertiarybutyl peroxyvaleric acid n-butyl ester, tl-
ditertiarybutylperoxy-3,3,5-)dimethylcyclohexane, α,α'-bis(tertiarybutylperoxy)-p-1 isopropylbenzene, 2.5
Examples include -dimethyl-2,5-di(tert-butylperoxy) to xine-3. These chemical crosslinking agents are usually used in an amount of 1 to 15 parts by weight per 100 parts by weight of the resin component.

To mix the bisphenol A-based brominated epoxy resin crosslinked product and other additives with the thermoplastic resin, a conventional mixer such as a hot roll, kneader, or panburi mixer can be used. Furthermore, these mixed proboscises may be pelletized using an extruder to form chips.

The thus kneaded composition is used as a raw material and formed into a sheet using a melt extruder. Next, the thermoplastic resin is crosslinked by subjecting the obtained sheet to crosslinking treatment. The crosslinking treatment is carried out by passing through a wire, using the above-mentioned chemical crosslinking agent, or using radiation therapy.

When using a chemical crosslinking agent, the crosslinking length is 140 to 2.
A range of 00°C for 1 hour to 30 minutes and 1 river is appropriate.

+ In the case of injected radiation therapy, the high-energy rays used include alpha rays, beta rays, beta rays, X-rays, accelerated proton beams,
There are rays such as rays and neutrons, but rays with high energy and neutrons are generally used. For example, the formed sheet is crosslinked by irradiating it with a wire lid of 1 to 50 Mr ad.

The foam of the present invention can be obtained by heating the thus obtained crosslinked sheet in a hot air atmosphere or on a salt bath to rapidly decompose the foaming agent.

Thus, according to the present invention, by incorporating a certain amount or more of the crosslinked bisphenol A-based brominated epoxy resin into the thermoplastic raw resin foam, bromination can be maintained on the sheet surface even after the molded sheet is stored at room temperature for a long period of time. The cross-linked epoxy resin does not bleed out and has a carbonization promoting effect during combustion, resulting in the following excellent effects.

(1) A long-term method 'α using a molded sheet is possible.

(2) During combustion, dripping in the wide combustion area is prevented by maintaining the shape, and the spread of fire can be prevented.

(3) When burned, it promotes carbonization and exhibits a highly flame-retardant acid.

8. The foam of the present invention can be used for building materials such as insulation ceiling materials, flooring materials, wall materials, etc., which particularly require a high degree of flame retardant acid, among the usual uses of Netsucho cast resin foams. suitable for

Next, the present invention will be explained based on practical examples.

Each measurement value in the practical column g is based on the following measurement method.

(1) Bromine content: A certain amount of foam is sampled and weighed accurately. This sample was decomposed using the flask combustion method, and the absorbed liquid was
Potentiometric titration with nitric acid solution using a silver electrode. The amount of bromine was determined from this titration curve, and the amount of bromine in the foam was calculated.

(2) Bleed-out: After storing the extruded bottom sheet for 30 days, the state of the sheet surface (stickiness, etc.) was observed and judged as bleed-out (af) (x), hard (○).

(5) Dripping property and shape retention A combustion test of a sample held horizontally determined the degree to which 1$8 portion of fuel drips (dripping property) and the degree to which it softens (shape retention) using the following evaluation criteria. It was shown in

There is no A-drip and the form retention fP is large.

B drips, but in a relatively small amount, and its shape retention is moderate.

There are many C-ni drips (and there is no shape retention at all.

(4) Amount of Carbon Production The carbonization state of the burnt part after extinguishing was determined and evaluated in the following three stages.

Large: The amount of carbon produced in the combustion part is large and the shape is maintained.

The part of the inside that is about to drip has solidified into a round shape and is partially carbonized.

Small: Almost no carbonized parts.

(5) Flammability A combustion test was conducted according to ASTM D1692-59T, and flame retardant acids were rated in the following three grades.

◎: Self-extinguishing note. Bunsen Parker's flaming fire burns, but
A state in which the flame disappears immediately when the flame is removed. ○: A state in which the flame disappears within 5 seconds after the flame of the Punsen burner is released.

Δ: A state in which the flame does not disappear within 5 seconds even if the flame of the Gunzen burner is released.

Example 1 Low-solubility polyethylene (manufactured by Tamashi Petrochemical Co., Ltd., MiraSonna 16
90 parts by weight of bispheno-) L/A brominated epoxy resin crosslinked product, 10 parts by weight of S and 10 parts of azodicarbonamide as a blowing agent were thoroughly mixed in a Henschel mixer. It was pelletized using an extruder.

The cross-linked bisphenol A-based brominated epoxy resin used here was made by mixing 100 parts by weight of E8B-400 (manufactured by Sumitomo Chemical, bromine content 46-50% by weight) with boron trifluoride monoether as a curing agent. A prepolymer obtained by reacting 4 parts by weight of amine at 100°C for 4 hours was powdered at room temperature and then heat-treated at 150°C for 15 minutes to obtain υ.

Using the above pellets as raw material, using a 30 mm diameter extrusion tank, 1
The sheet was melt extruded at 35'C to obtain a sheet with a thickness of 1.6 mm. This sheet was crosslinked by irradiating it with 5 Mrad using an electron beam irradiation device.

This crosslinked sheet is heated and foamed at 220°C in a salt bath to form polyethylene. I got the package. The density of this foam was Q, 0509/Cm'. On the other hand, when the extruded sheet was kept at room temperature for 30 days, no bleed-out was observed.

The flammability of this foam was investigated and the results are shown in Table 1. Although it burned in the flame of a Bunsen burner, it extinguished immediately when the flame was removed after the fire was over, showing self-extinguishing properties. In addition, no drip phenomenon was observed during combustion, and after extinguishing the fire, a large amount of carbon was produced in the combustion part and the shape retention was good.

Examples 2 to 5, comparative rows 1 to 4 Polyethylene; bisphenol A-based brominated epoxy resin and its crosslinked product: flame retardant, decabromodiphenyl ether; flame retardant aid, antimony trioxide; inorganic filler, aluminum oxide Table 1 Molding was carried out in the same manner as in Example 15'lJ1 except that the proportions shown in the resin composition were used.
A polyethylene foam was obtained by crosslinking and foaming.

In Examples 2 to 5, there was no bleed-out during long-term storage of the molded sheets.

In Examples 3 to 5, the bromine content was 4.0% by weight or more, and no dripping occurred. It produced a large amount of carbon, had good shape retention, and was self-extinguishing.

In Example 2, the bromine content due to the addition of the bigphenol A-based brominated epoxy resin crosslinked product was 2.2% by weight, and compared to Examples 3 to 5, the shape retention was inferior, and the flame and soul pillars were also poor. Although not self-extinguishing, it achieves the objectives of the invention.

In Comparative Example 1.2, the bisphenol A-based brominated epoxy resin was added as is without crosslinking, and as in Example 1.2, the shape retention during combustion and the soaked twist resistance were improved. However, there was a drawback that the molded sheet caused a bleed effect on the upper part of the retainer.

In comparison column 3, the amount of bisphenol A-based brominated epoxy resin added was small and did not meet the requirements of the present invention, so dripping could not be prevented.

In Comparative Example 4.5, a commonly used brominated flame retardant and an inorganic filler were used in place of the crosslinked pipephenol A-based brominated epoxy resin, but the bromine content was 14 to 15% by weight. %, drip cannot be prevented, and the difference with the present invention is clear.

As detailed above, according to the present invention, bc kanbo'a
It is possible to provide a foam that has no bleeding from the molded sheet inside, prevents the drip phenomenon during combustion, and exhibits high twist resistance.

Claims (1)

[Claims] A foam mainly composed of a thermoplastic resin mixed with a bisphenol A-based brominated epoxy resin crosslinked product, in which bromine in the bisphenol A-based brominated epoxy resin crosslinked product is 2.0% by weight or more based on the foam. A thermoplastic resin foam containing