JPH0618981B2 - Flame-retardant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention comprises an ABS resin and a vinyl chloride resin,
The present invention relates to a flame-retardant resin composition having excellent processability, impact resistance, and thermal stability.

[Conventional technology]

Conventionally, high-impact polystyrene resins and acrylonitrile-based thermoplastic resins that are used in the fields of electric equipment parts, automobile parts, building materials, etc. have the characteristics of excellent impact resistance and rigidity, and extremely good moldability. A rubber-containing impact-resistant polystyrene-based resin such as a butadiene-styrene copolymer (hereinafter referred to as ABS resin) has been often used.

However, for the resins used in this field in recent years,
Higher flame-retardant properties are required, and to some extent, the development of higher flame-retardant resins in place of the above-mentioned polystyrene resins, which are flammable, is desired. Things have been proposed.

For example, there is a flame-retardant resin composition containing a low-molecular-weight flame retardant represented by a phosphorus-containing compound such as a halogenated ester, an aromatic halogen-containing compound, a phosphoric acid ester, or a halogenated phosphoric acid ester.

However, since these flame retardants are chemically unstable low molecular weight compounds and must be added in a considerable amount in order to impart a high degree of flame retardancy to the resin, the mechanical strength of the resin, Somehow, the impact strength will drop significantly,
Molding processability is hindered by coloring caused by thermal decomposition during molding process, and weather resistance is significantly deteriorated.
In many cases, the commercial value of the product is impaired.Furthermore, since flame retardants are generally expensive, they have the drawbacks of significantly increasing the cost of the product. It is difficult to obtain a resin that can be used for.

On the other hand, focusing on the fact that it is easy to obtain a high degree of balance between flame retardancy and impact strength, flame retardancy obtained recently by mixing halogen-containing compounds such as polyvinyl chloride resin and chlorinated polyethylene with other resins. Many resin compositions have been proposed.

For example, a flame-retardant resin composition comprising a polyvinyl chloride resin and an ABS resin is known (Japanese Patent Publication No. 48-528).

The resin composition is derived from the properties of the polyvinyl chloride resin, and certainly has excellent mechanical strength such as impact strength and rigidity, and a resin having a high degree of flame retardancy can be obtained, but the polyvinyl chloride resin is chemically Since the resin composition is poor in thermal stability because it is unstable in nature and is prone to thermal decomposition, the moldability is remarkably lowered in combination with the poor fluidity of the polyvinyl chloride resin. Have

On the other hand, it is obvious that a heat stabilizer such as a lead-based compound or a tin-based compound is added to improve molding processability by increasing the thermal stability of polyvinyl chloride, but The amount used is naturally limited due to the important effects on liquidity and physical properties and cost.

Also known is a method of improving the molding processability of polyvinyl chloride by reducing the content of molecules having an asymmetric structure (branching, double bond, etc.) in the polymer by ionic polymerization or the like. However, there are industrial problems in terms of polymerization rate and yield. Furthermore, as a method of improving the resin moldability, there is a method of increasing the resin fluidity and suppressing the molding temperature to enhance the thermal stability of the resin. Is likely to decrease, and a sufficient effect cannot be obtained.

On the other hand, a flame-retardant resin composition (US Pat. No. 3494982) composed of chlorinated polyethylene and ABS resin is also known. This composition has a slightly better thermal stability than the polyvinyl chloride resin composition, but has the drawback of poor moldability due to poor flowability.

As described above, no conventional flame-retardant resin composition has been found to have practical use as a molding material that simultaneously satisfies molding processability, impact resistance, and weather resistance, which are important as commercial values.

[Problems to be Solved by the Invention] An object of the present invention is to provide a flame-retardant flame-retardant material having molding processability that can be put to practical use as a molding material that has been difficult with conventional compositions, and also having impact resistance. The purpose of the present invention is to provide a resin composition.

[Means for solving problems]

The present inventor has conducted extensive studies to achieve the above object,
The inventors have found that a flame-retardant resin composition excellent in processability, impact resistance, and thermal stability can be obtained by combining an ABS resin and a specific vinyl chloride resin, and arrived at the present invention.

That is, the resin composition of the present invention has a secondary rearrangement point of −10 ° C. when A) 20 to 70% by weight of ABS resin and B) homopolymer are used.
When the homopolymer is made with 60 to 90 parts by weight of the following alkyl acrylate and / or alkyl methacrylate, 5 to 39 parts by weight of monomers having a secondary rearrangement point of 0 ° C. or higher and 1 to 30 parts by weight of a polyfunctional monomer are added. Copolymer of 1 to 30
It is characterized by comprising 30 to 80% by weight of a vinyl chloride resin obtained by graft-copolymerizing 70 to 99 parts by weight of vinyl chloride with respect to 1 part by weight.

The details will be described below.

The content of ABS resin in the flame-retardant resin composition of the present invention is 20-
It is 70% by weight, particularly preferably 30 to 65% by weight. If it is less than 20% by weight, the workability is poor, and if it exceeds 70% by weight, it is difficult to maintain flame retardancy.

Polybutadiene rubber, which is a raw material for ABS resin polymerization,
Polybutadiene or 50% by weight or more of butadiene and 50% by weight or less of a monoolefin monomer copolymerizable therewith, aromatic vinyl compounds such as styrene, alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; methyl methacrylate , An alkyl methacrylate such as ethyl methacrylate and butyl methacrylate; a copolymer with a vinyl cyanide compound such as acrylonitrile.

The vinyl cyanide compound used in the ABS resin graft polymerization is acrylonitrile, methacrylonitrile or the like, and the aromatic vinyl compound is styrene or α.
-Methyl styrene, chlorostyrene, etc. are typical, and the use ratio is preferably 10 to 50 parts by weight of vinyl cyanide compound and 20 to 80 parts by weight of aromatic vinyl compound to 10 to 50 parts by weight of the butadiene rubber. .

In the graft polymerization, a small amount of vinyl monomers copolymerizable with vinyl cyanide compounds and aromatic vinyl compounds can be used.

Any of the above-mentioned polymerizations can be easily carried out by a conventionally known method such as suspension polymerization and emulsion polymerization, but emulsion polymerization is particularly preferable.

The content of the vinyl chloride resin in the flame-retardant resin composition of the present invention is 30 to 80% by weight, preferably 40 to 70% by weight.

If the proportion of the vinyl chloride resin exceeds 80% by weight, the impact strength and molding processability of the resin composition deteriorate, which is not desirable. On the other hand, if the proportion is less than 30% by weight, the high flame retardancy targeted by the present invention cannot be obtained.

The graft polymerization raw materials used for the vinyl chloride resin in the present invention are copolymers of alkyl acrylate and / or alkyl methacrylate with monomers and polyfunctional monomers (hereinafter referred to as acrylic copolymers) and vinyl chloride.

When the homopolymer is used as the alkyl acrylate and the alkyl methacrylate, the secondary transition point of the homopolymer is −
Below 10 ° C, such as ethyl acrylate, n-
Propyl acrylate, iso-butyl acrylate, n
-Butyl acrylate, n-hexyl acrylate, 2
-Ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, and n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, lauryl methacrylate, and the like, which contribute to impact resistance.

Alkyl acrylate and / or alkyl methacrylate acts as a soft segment, and the amount used is preferably 60 to 90 parts by weight per 100 parts by weight of other copolymerization raw materials. If it exceeds 90 parts by weight, improvement in strength cannot be expected. If the amount is less than the range, the impact resistance decreases, which is not preferable.

The monomers of the present invention have a secondary rearrangement point of 0 ° C. or higher when formed into a homopolymer, and function as a hard segment by copolymerization, such as styrene and α-
Aromatic vinyls such as methylstyrene and vinyltoluene, unsaturated nitriles such as acrylonitrile and methacrylonitrile, vinyl acetates such as vinyl acetate and vinyl propionate, vinyl ethers such as butyl vinyl ether, octyl vinyl ether and lauryl vinyl ether, methyl Examples thereof include alkyl acrylates, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and propyl methacrylate, which may be used alone or in a mixture of two or more kinds.

The amount of the monomers used is preferably 5 to 39 parts by weight.
If it is less than part by weight, the strength cannot be improved, and if it exceeds 39 parts by weight, impact resistance is lowered, which is not preferable. Methyl methacrylate, methyl acrylate, acrylonitrile, and styrene are preferable especially when improvement in strength is expected.

The polyfunctional monomer is an alkyl acrylate and / or
Or a monomer that causes cross-linking or the like in alkyl methacrylate, such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-
Propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate etc Examples thereof include di- or triallyl compounds and divinylbenzene.

The amount of the polyfunctional monomer used is preferably from 1 to 30 parts by weight. If it is less than 1 part by weight, the strength cannot be expected to be improved, and if it exceeds 30 parts by weight, the impact resistance is not improved.

Copolymers of the alkyl acrylate and / or alkyl methacrylate used in the present invention with monomers and polyfunctional monomers are emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization, and other commonly known emulsifiers. It can be obtained using a dispersant and a catalyst agent, but it is preferable to employ emulsion polymerization.

The amount of the acrylic copolymer used as the trunk polymer of the graft copolymerization for obtaining the vinyl chloride resin component of the present invention is 100 parts by weight in total with the amount of vinyl chloride which is another raw material of the graft copolymerization. 1 to 30 parts by weight per unit is suitable. If the amount of the acrylic copolymer used is less than 1 part by weight, the impact resistance is insufficient, and if it exceeds 30 parts by weight, the impact resistance is improved but the strength is lowered, which is not preferable.

As the graft copolymerization method of the present invention, an aqueous suspension polymerization method,
Examples thereof include an aqueous emulsion polymerization method, a solution polymerization method and a solutionless polymerization method, but an aqueous suspension polymerization method is preferable. When the aqueous suspension polymerization method is carried out, the total weight ratio of the acrylic copolymer of the trunk polymer, the vinyl chloride monomer and water is 1: 1 to 1: 5, preferably 1: 1 to 1: 3. The method for obtaining a graft copolymerized vinyl chloride resin by a general suspension polymerization method is, for example, pure water, a suspension stabilizer such as hydroxypropylmethylcellulose, a radical polymerization initiator, and if necessary, in a jacketed polymerization reactor. Then, a degree-of-polymerization reducing agent is added thereto, the acrylic copolymer is added thereto and suspended, and then the air in the can is eliminated, and then vinyl chloride is charged together with other vinyl compounds as required. After that, heat with the jacket in the can to dissolve the acrylic copolymer in vinyl chloride,
Initiate graft copolymerization. Graft copolymerization is an exothermic reaction, and the internal temperature is controlled from the jacket if necessary. After completion of the reaction, unreacted vinyl chlorides are removed outside the can to obtain a slurry-like graft copolymer resin. The slurry is dehydrated and dried according to a conventional method to obtain a graft copolymerized vinyl chloride resin. The method of charging the polymerization reactor is not limited, and the acrylic copolymer of the charging raw materials such as pure water, suspension stabilizer, acrylic copolymer and vinyl chloride is dissolved in vinyl chloride. The method of charging after that is also adopted.

In the graft copolymerization, other monomers may coexist as long as the impact resistance, weather resistance and flexural modulus are not lowered.

The resin composition of the present invention may optionally contain other additives such as a flame retardant, an ultraviolet absorber, an antioxidant, a colorant, a lubricant and a heat stabilizer.

The resin composition of the present invention is a mixing roll, a co-kneader,
It is easily dissolved and mixed by a kneading machine such as a Banbury mixer and an extruder.

The resin composition of the present invention thus obtained can be widely used in the fields of electric parts, automobile parts, building materials, office machine parts and the like, which require high flame retardancy.

The present invention will be described in detail below with reference to examples and reference examples.

Each physical property value in the present invention was measured by the following methods.

(1) Measurement of molding processability (fluidity) Using 1g of extruded pellets, a die with an inner diameter of 1mm and a length of 10mm, a pressure of 150kg / cm ² and a temperature of 200 ° C was used with a Koka flow tester. The flow rate was measured.

(2) Measurement of molding processability (thermal stability) (2) -1 CR thermal stability test (static thermal stability) Time (minutes) until decomposition starts according to JIS K-6723 method
Was measured. However, the temperature was 200 ° C.

(2) -2 Dynamic thermal stability 32 g of extruded pellets were charged into a batch mixer blast graph with a rotor mixer with an internal volume of 30 cc and a temperature of 190 ° C, and the rotation speed was 50
Kneading was performed under the conditions of rpm and load of 10.0 kg, and the time (minutes) from when the tokule descended to a steady state and when it started to rise again was measured.

(3) Impact strength measurement In accordance with ASTM-256 method, injection molding temperature with a 4OZ injection molding machine 1
Izod impact strength was measured using an Izod impact test piece obtained by molding under conditions of 80 °, 200 °, 200 ° C and a molding cycle of 1 minute. However, a notch was used for the notch.

(4) Flame retardant UL-94 method sample thickness 1/8 inch test piece used.

〔Example〕

Examples 1 to 6 and Reference Examples 1 to 11 (1) Production of ABS Resin Emulsion polymerization was carried out at 60 ° C. based on the amounts of raw materials used shown in Table 1 to obtain polymers (A) -1 to 10. The composition of the solid polybutadiene latex used is as follows.

PB-1 …… Butadiene content 100% (weight% 3 or less same) PB-2 …… Butadiene content 60%, Styrene content 40% PB-3 …… Butadiene content 60%, Acrylonitrile content 40% PB-4 …… Butadiene 40% min, 40% styrene, 20% acrylonitrile The amounts of raw materials used in Table 1 are parts by weight (the same applies to Table 2 and below). (2) Manufacture of vinyl chloride resin Aqueous suspension polymerization was carried out at 63 ° C. based on the amount of raw materials used to obtain polymers (B) -1 to 10.

The secondary transition temperature of the acrylic resin homopolymer is as follows.

Poly-n-butyl acrylate …… -56 ℃ Poly-2-ethylhexyl acrylate -20 ℃ Methyl acrylate …… 0 ℃ Methyl methacrylate …… 45 ℃ (3) Production of Resin Composition of the Present Invention The ABS resin obtained in (1) above and the vinyl chloride resin obtained in (2) above are mixed in the proportions shown in Tables 3 and 4, Further, as a stabilizer, dibutyltin mercaptide 2.
5 parts by weight of 5 with a super mixer (Kawata Manufacturing)
After mixing at 90 ℃ for 10 minutes, use a 40mmφ extruder.
It was melt-kneaded at 200 ° C. and pelletized.

Next, a 4-ounce injection molding machine was used to prepare test pieces for measuring physical properties. In this case, the molding temperature is 18 cylinder temperature.
The temperature was set to 0, 200, 200 ℃. Using the pellets and test pieces thus obtained, the above-mentioned various physical property tests were conducted.

The evaluation results are shown in Tables 3 and 4 together with the reference examples.

As is clear from Tables 3 and 4, the composition of the present invention is excellent in processability, physical strength and flame retardancy.

[Effects of the Invention] As described in detail above, the present invention provides a flame-retardant resin composition excellent in processability, impact resistance, and thermal stability, and improves the quality of the flame-retardant resin and expands the use thereof. The contribution is extremely large.

Claims (1)

[Claims] 1. When A) 20 to 70% by weight of ABS resin and B) homopolymer are used, the secondary rearrangement point thereof is -10 ° C.
When the homopolymer is made with 60 to 90 parts by weight of the following alkyl acrylate and / or alkyl methacrylate, 5 to 39 parts by weight of monomers having a secondary rearrangement point of 0 ° C. or higher and 1 to 30 parts by weight of a polyfunctional monomer are added. Copolymer of 1 to 30
A flame-retardant resin composition comprising 30 to 80% by weight of a vinyl chloride resin obtained by graft-copolymerizing 70 to 99 parts by weight of vinyl chloride with respect to 1 part by weight.