JPS6092344A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:The titled composition having excellent dispersion stability, mechanical properties, moldability, and flame retardancy, made by incorporating a specified styrene-methyl methacrylate graft polymer into a composition comprising a PS resin and a PVC resin. CONSTITUTION:A prepolymer with one carboxylic acid terminal having a number-average molecular weight of 1,000-20,000, made by the radical polymeriza- tion of methyl methacrylate in the presence of thioglycolic acid is reacted with glycidyl methacrylate to obtain methyl methacrylate macromonomer. The macromonomer and styrene monomer are graft polymerized to obtain a styrene-methyl methacrylate graft polymer (B) having a number-average molecular weight of at least 5,000. Then, 0.3-30pts.wt. component (B) is incorporated into 100pts.wt. composition (A) comprising a PS resin and a PVC resin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin composition in which a styrene-methyl methacrylate graft polymer is added as a compatibilizer to a composition of a polystyrene resin and a polyvinyl chloride resin.

Both polystyrene resins and polyvinyl chloride resins are rigid thermoplastic resins, and each has a wide range of uses.

In general, polystyrene resin has excellent properties such as beautiful appearance, good dimensional stability, and easy processability, so it is widely used in electrical appliances, automobile parts, general goods, etc. through processing processes such as injection molding and extrusion molding. It is used. However, it has drawbacks such as poor impact strength, easy flammability, and the generation of large amounts of black smoke when burned, so its uses are often limited. In an attempt to improve the poor impact strength of polystyrene resins, a common method is to coexist with butadiene rubber during production and carry out craft polymerization, and a large amount of this material is on the market as an impact-resistant grade of polystyrene resins. . On the other hand, commercially available flame retardants can be used to impart flame retardancy to polystyrene resin, but a large amount of flame retardant is required to obtain a sufficient effect, and as a result, the inherent physical properties of polystyrene resin may deteriorate. There are problems with the invitation level. In recent years, the U.S.
As the L standard is strengthened, there is an increasing demand for flame retardant flammable polymers.

In addition, polyvinyl chloride resin is a general-purpose resin that is produced in large quantities at low cost, and is widely used due to its excellent flame retardancy and chemical resistance. In order to overcome these drawbacks, blends with various polymers have been considered for a long time.For example, in order to improve impact resistance, acrylonitrile-butadiene copolymer (hereinafter referred to as NBR) has been studied. Rubber components such as ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA), chlorinated polyethylene (hereinafter abbreviated as CPE), acrylonitrile-butadiene-styrene copolymer (hereinafter abbreviated as ABS), methylmethacryle-thobutadiene- It is known that graft polymers such as styrene copolymer (hereinafter abbreviated as MBS) are effective.
It is known that blending with acrylonitrile-styrene copolymers, methyl methacrylate-acrylic acid ester copolymers, etc. is effective in improving processability.

Both polystyrene resin and polyvinyl chloride resin are general-purpose hard thermoplastic resins, but as mentioned above, they have different features and are used in large quantities for applications that take advantage of their respective characteristics. On the other hand, due to the inherent drawbacks of resins, their uses are often limited.

Attempts to create polymer blends that take advantage of the strengths of polystyrene resins and polyvinyl chloride resins and compensate for their shortcomings are considered to be very interesting and of great industrial significance. If thermoplastic resins that have both the excellent moldability of polystyrene-based resins and the excellent flame retardancy of polyvinyl chloride-based resins can be obtained through polymer blends, the range of uses will be greatly expanded.

Unfortunately, however, the two resins are not compatible with each other.
When melted and mixed, it enters a clear discontinuous composition region! do. The components in each of these regions do not adhere well to each other, resulting in a brittle, low-strength molding.

In order to mix mutually incompatible polymers, it is necessary to add some kind of chemical modification to one or both of the polymers so that they interact. However, attempts to modify resin components used in large quantities through chemical reactions require enormous costs and labor. This is move 11! This is not a wise method, as it goes against the spirit of polymer blending, which is to obtain a resin with excellent physical properties at a low cost and in a cost-effective manner.

It would be of great practical value if a small amount of a compatibilizer could be added as a third component in addition to the resin to be blended to improve the miscibility of each component polymer.

There are surprisingly few patent applications dealing with polymer blends of polystyrene resins and polyvinyl chloride LT fats. There are even fewer patent applications that use some kind of compatibilizer or dispersion aid to improve the blend compatibility of polystyrene resins and polyvinyl chloride resins, and as far as the present inventors know, there are only a few There are only .3 examples.

For example, JP-A-51-92856 states that compatibility and melt fluidity are improved by adding a styrene-conjugated diolefin block copolymer as the sixth component.

Further, in JP-A-57-427!54, a chlorinated styrene-butadiene block copolymer is used as a compatibilizing agent to obtain a composition with improved compatibility.

In the former example, since a commercially available block polymer is used as is, it does not have an anchor segment for the vinyl chloride resin, and its compatibilizing ability is questionable. fact,
Almost no improvement in tensile strength was observed. Moreover, in the latter example, it is necessary to chlorinate a commercially available block polymer, which imposes severe cost constraints.

In both cases, commercially available block polymers are used as compatibilizers either as they are or after chlorination. Graft polymers are used based on the concept of compatibilizers, and styrenic resins with practical physical properties and chlorinated polymers are used as compatibilizers. There are no reports of obtaining blends of vinyl resins. The reason for this is that conventional methods for synthesizing graft polymers, such as chain transfer methods using peroxides, radiation grafting methods, and polymer initiator methods, have low grafting rates and inevitably produce large amounts of homopolymers as by-products. This is because it had some drawbacks.

As a result of intensive research in view of these drawbacks of conventional methods, the present inventors have discovered that a graft polymer with a clearly controlled structure can be used as a 1/2 polymer of polystyrene resin and polyvinyl chloride resin.
It has been found that the miscibility of the resin composition is significantly improved and a resin composition with excellent performance is obtained.

That is, the present invention provides a thermoplastic resin obtained by blending 0.3 to 30 parts by weight of a styrene-methyl methacrylate graft polymer produced using a macromonomer to a composition consisting of a polystyrene resin and a polyvinyl chloride resin. It is a composition. If the content of one of the resins in 100 parts by weight of the blend of polystyrene resin and polyvinyl chloride resin is less than 5 parts by weight, the physical properties of that resin will not be sufficiently reflected in the blend, and there will be no point in blending. Therefore, it is desirable that the amount of the polystyrene resin is 95 to 5 parts by weight, and the polyvinyl chloride resin is 5 to 95 parts by weight.

The macromonomer in the present invention means a polymer of styrene and methyl methacrylate having a relatively low molecular weight (1.000 to 20,000 in number average molecular weight) having a radically polymerizable functional group at one end of the molecular chain. Examples of the terminal polymerizable functional group of the macromonomer in the present invention include those of vinyl polymerization type such as acryloyloxy, methacryloyloxy, allyloxy, and styryl.

In addition, the graft polymer used in the present invention can be easily synthesized by radical copolymerization of a radically polymerizable monomer and the above-mentioned macromonomer, and specifically, a type selected from styrene macromonomer and methyl methacrylate macromonomer. It is a graft polymer obtained by radical copolymerization of the above two monomers and one or more selected from styrene monomers and methyl methacrylate monomers. The method for synthesizing graft polymers using macromonomers as described above is as follows:
(1) The content of homopolymers in the branch and trunk components is very low.

(2) The molecular weight of the branch components, the molecular weight of the entire graft polymer, and the weight ratio of the branches to the trunk can be easily controlled.

(3) Combinations of branch components and trunk components can be freely selected depending on the purpose.

With these characteristics, it is possible to easily obtain a high-performance graft polymer that cannot be obtained by conventional graft polymer synthesis methods.

For example, a graft polymer with polymethyl methacrylate as a branch and polystyrene as a trunk can be synthesized by radical polymerizing methyl methacrylate in the coexistence of thioglycolic acid to form a one-terminal carboxylic acid prepolymer with a molecular weight of 1.000 to 20,000. This is reacted with glycidyl methacrylate to obtain a macromonomer having a methacrylate terminal group. By copolymerizing this macromonomer with a styrene monomer as a copolymerization component, a graft polymer having polymethyl methacrylate as the branches and polystyrene as the trunk can be obtained.

Even if the branches and trunk are reversed, the whole can be manufactured in the same way.

There are two types of graft polymers used to make polystyrene resin and polyvinyl chloride resin compatible: a polystyrene segment that is compatible with polystyrene resin, and a polymethyl methacrylate segment that is highly compatible with polyvinyl chloride resin. It is necessary to be a graft polymer that has segments within the same polymer molecule. That is, the structure of the graft polymer is as follows: (1) A polymethyl methacrylate (branch)-polystyrene (trunk) type graft polymer obtained by copolymerizing a methyl methacrylate macromonomer and a styrene monomer.

+2) A polystyrene (branch)-polymethyl methacrylate (trunk) type graft polymer obtained by copolymerizing a styrene macromonomer and a methyl methacrylate monomer.

(3) Polystyrene (branch)-polymethyl methacrylate@)-styrene/methyl methacrylate random copolymer (trunk) type obtained by copolymerizing methyl methacrylate macromonomer, styrene macromonomer, methyl methacrylate monomer, and styrene monomer craft polymer.

(4) A polystyrene (branch)-polymethyl methacrylate (branch)-polystyrene (trunk) type graft polymer obtained by copolymerizing a methyl methacrylate macromonomer, a styrene macromonomer, and a styrene monomer.

(5) Polystyrene (branch)-polymethyl methacrylate (branch)-polymethyl methacrylate (
Stem) type graft polymer.

etc. are valid. The styrene-methyl methacrylate graft polymer used in the present invention may be a graft polymer obtained by using styrene monomers and methyl methacrylate monomers in combination with other copolymerized monomers as described above.

Other copolymerizable monomers include acrylonitrile,
Examples include N,N-dimethylacrylamide, vinyl acetate, maleic acid, butadiene, and the like.

When these graft polymers are used as compatibilizers1, they concentrate at the interface between polystyrene resin and polyvinyl chloride resin, and the polystyrene segment in the graft polymer molecule becomes polystyrene resin, and the polymethyl methacrylate segment becomes polychloride. By being compatible with the vinyl resin, the interface between different polymers is firmly bonded.

Graft polymers by conventional methods such as the above-mentioned chain transfer method using peroxide, radiation grafting method, polymer initiator method, etc.
Because the lengths of the branch components are irregular or the density of the branch components is low, the compatibility with the polystyrene resin or polyvinyl chloride resin is not sufficiently exhibited.

As a method for blending the thermoplastic resin composition of the present invention, kneading may be performed using an open rule, Banbury mixer, extruder, etc. Methods such as solution blending and then distilling off the solvent are also possible. Although the order of addition of the three components, polystyrene resin, polyvinyl chloride resin, and graft polymer, is not particularly limited, it is preferable to add the minor component, the graft polymer, and the major component in this order.

2 The mechanical strength of the composition of the present invention is determined by adding 0.3 parts of styrene-methyl methacrylate graft polymer to 100 parts by weight of the composition of polystyrene resin and polyvinyl chloride resin.
Significant improvement is achieved by adding ~60 parts by weight.

For example, regarding tensile strength, if no graft polymer is added, the composition-strength curve will be a downward convex curve typical of incompatible blends, but when the graft polymer is added to polystyrene resin and polyvinyl chloride resin, Compound 100
By specifically adding 0.3 to 30 parts by weight, linearity with respect to the composition can be improved (see FIG. 2 of Example 6).

The molecular weight of the styrene-methyl methacrylate graft polymer added as a compatibilizer is affected by various factors such as the blending method, blend composition, composition and amount of graft polymer added, and the molecular weight of the polystyrene resin and polyvinyl chloride resin. Although not particularly limited, the number average molecular weights of T* and # are preferably 5,000 or more, and io,
More preferably, it is equal to or greater than ooo. If the number average molecular weight is less than 5,000, the anchoring effect based on the entanglement of polymer chains with polystyrene resins and polyvinyl chloride resins belonging to the oligomer region becomes weak, and the bonding effect at the interface tends to become small. The copolymerization composition of the styrene-methyl methacrylate graft polymer used as a compatibilizer depends on the blending method, blend composition, amount of styrene-methyl methacrylate graft polymer added, polystyrene resin, molecular weight of polyvinyl chloride resin, and styrene-methyl methacrylate. Although not particularly limited as it is affected by various factors such as the molecular weight of the graft polymer, polystyrene/polymethyl methacrylate) =
It is preferably 9515 to 5/95 (wt/wt). If the proportion of one component is less than 5 wt%, the compatibilizing effect will be small.

Regarding the amount of styrene-methyl methacrylate graft polymer added as a compatibilizer, if the amount added is less than 0.3 parts by weight per 100 parts by weight of the blend of polystyrene resin and polyvinyl chloride resin, compatibilization will occur. The effect of styrene-methyl methacrylate graft polymer is insufficient, and if it exceeds 30 parts by weight, it is not preferable from the viewpoint of cost and also reduces the physical properties of the resin composition. Within range.

When using the thermoplastic resin composition of the present invention, if impact resistance is required depending on the application, commonly used reinforcing agents such as ABS, MBS%NBR, EVA may be used.
, CPE, styrene-phtadiene block copolymer, etc. can be used. The amount of these reinforcing agents added is
A suitable amount is 1 to 20 parts by weight per 100 parts by weight of the resin composition. If the amount added is less than 1 part by weight, the effect as a reinforcing agent will be insufficient, and 20. If the amount exceeds lf parts by weight, the rigidity of the resin composition decreases, which is not preferable. All of these reinforcing agents are polymers that are compatible with polyvinyl chloride resin or polystyrene resin, and do not have an adhesive effect at the polystyrene resin/polyvinyl chloride resin interface.

The polystyrene resin and polyvinyl chloride resin in the present invention are resins whose main components are polystyrene and polyvinyl chloride, respectively, and the subcomponents may be physically blended or copolymerized. It may be introduced into the polymer molecule, or it may be a component introduced by graft polymerization.

As a copolymer component in polystyrene resin, α-
Methylstyrene, acrylonitrile, (meth)acrylic acid, (meth)acrylic ester, maleic anhydride, etc.
Examples of the graft component include butadiene rubber, and examples of the blend component include butadiene rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, and the like.

As a copolymer component in polyvinyl chloride resin, α
-Olefin, vinyl acetate, vinylidene chloride, (meth)
Acrylic acid, (meth)acrylic acid ester, vinyl ethers, etc. Graft components include EVA, ethylene-propylene-diene monomer terpolymer, thermoplastic polyurethane, etc. Blend components include ABS, MBS, N
BR16 EVA, CPE, acrylonitrile-ethylene propylene diene monomer 3 main valve li combination-, z, chiv
Examples include low-molecular plasticizers such as y copolymer (AES), chlorinated polyvinyl chloride, various linear polyesters, and dialkyl phthalate.

The amount of these subcomponents is 0 to 50 parts by weight per 100 parts by weight of the polystyrene resin or polyvinyl chloride resin. If the amount used exceeds 50 parts by weight, it is not preferable because the original properties of the main component, polystyrene or polyvinyl chloride, will be impaired.

The thermoplastic resin composition of the present invention has excellent dispersion stability and improved mechanical properties, and can be used for various practical applications. Moreover, the practical value is extremely great in that a molding resin composition that has both the excellent moldability of a polystyrene resin and the flame retardancy of a polyvinyl chloride resin can be obtained easily and inexpensively.

The present invention will be explained in more detail by referring to Reference Examples, Comparative Reference Examples, Examples, and Comparative Examples below.

In addition, parts on each side represent parts by weight, and % represents weight %.

Reference Example 1 Methylmethac1), rate macromonomer synthesis stirrer, reflux condenser, dropping funnel, thermometer and N2
Add acetone 160 to a glass flask equipped with a gas inlet.
A mixed solvent of 660 parts of toluene was charged, N was introduced under reflux, and 5 parts of initiator azobiscyanovaleric acid (hereinafter referred to as ACVA), 500 parts of methyl methacrylate (hereinafter referred to as MMA), and thio as a chain transfer agent were added. Polymerization was carried out by continuously dropping a mixed solution of 4.6 parts of glycolic acid (hereinafter abbreviated as TGA) for 6 hours. After that, the polymerization was completed by heating for 2 hours.

Next, after distilling off a part of the acetone from the reaction solution, 2% of triethylamine (hereinafter abbreviated as TEA) as a catalyst,
Hydroquinone monomethyl ether (
(hereinafter abbreviated as MQ) 1.5 for 200 ppm and acid value
twice the molar amount of glycidyl methacrylate (hereinafter abbreviated as GMA)
) was added thereto, and the mixture was reacted for 8 hours at a reaction temperature of 110°C. The reaction rate determined from the decrease in acid value was 98%.

The reaction solution was poured into 10 times the volume of n-hexane to precipitate it, and then dried under reduced pressure at 80°C to obtain 482 parts of MMA macromonomer. The polystyrene equivalent molecular weight determined by gel permeation chromatography (hereinafter referred to as GPC) was 10,500 (number average) and 20,000 (weight average).

Reference Example 2 Synthesis of Styrene Macromonomer 100 parts of styrene and 50 parts of toluene were charged into the same apparatus as in Reference Example 1, and while maintaining the solution temperature at 100°C while introducing N2, T
A mixed solution of 3.68 parts of GA, 1 part of azobiscyclohexanecarbonitrile (hereinafter abbreviated as ACFIN), and 50 parts of toluene was continuously added dropwise for 7 hours to carry out polymerization.

Next, TEAo, 5%, MQ 200pp was added to the above reaction solution.
GMA was added in a molar amount 15 times the molar value and acid value, and the mixture was reacted at a reaction temperature of 100° C. for 65 hours. The reaction rate was 99%. The reaction solution was poured into 10 times the volume of methanol (2) to precipitate and dry under reduced pressure at 50°C to obtain 134 parts of styrene macromonomer.The molecular weight in terms of polystyrene by GPC was 5.7θO (several tens of 90%) and It was 18.0 DD (weight average).

Reference Example 5 Synthesis of Styrene-MMA Graft Polymer 50 parts of styrene, 25 parts of the MMA macromonomer synthesized in Reference Example 1, and 25 parts of benzene were placed in a glass flask equipped with a stirrer, a reflux condenser, a thermometer, and a gas inlet. After charging and adjusting the solution temperature to 100 °C while introducing N2, AC
375 parts of HNo was added and reacted. After 6 hours of reaction time, 25 parts of benzene and 2 parts of A CHN O were added, and the reaction was continued for an additional 4 hours. The conversion rate of styrene monomer was 87%.

After diluting the reaction solution with tetrahydrofuran (hereinafter abbreviated as THF), it was poured into 10 times the volume of methanol to precipitate it,
Drying was performed under reduced pressure at 80°C to obtain 52 parts of styrene-MMA graft polymer. Polystyrene equivalent molecular weight by GPC is 30.000 (number average) and 156.0DD
(weight average).

Reference Example 4 Styrene-MMA Graft Polymer Kananari Into the same apparatus as in Reference Example 3, 30 parts of MMA, 15 parts of the styrene macromonomer synthesized in Reference Example 02, 15 parts of toluene, and 25 parts of AIBNo were charged, and the mixture was heated for 70 minutes under the introduction of N2.
The reaction was carried out at ℃ for 4 hours. The conversion rate of MMA was 91.2%.

The reaction solution was diluted with toluene, poured into 10 times the volume of methanol to precipitate it, and then dried under reduced pressure at 80°C to obtain 693 parts of a styrene-MMA graft polymer. G.P.
The polystyrene equivalent molecular weight according to C is 20,000 (number average) and 1 o, o o.

(weight average).

Reference Example 5 During the synthesis of styrene-MMA graft polymer, 5 parts of styrene, 5 parts of MMA,
5 parts of MMA macromonomer synthesized in Reference Example 1, 5 parts of styrene macromonomer synthesized in Reference Example 2, 2 parts of toluene
0 parts, A CHN O, 4 parts, N2 introduction lower 90
The reaction was carried out at ℃ for 4.5 hours.

The reaction solution was poured into 10 times the volume of methanol to precipitate it, and then dried under reduced pressure at 80°C to obtain ~16.34 parts of styrene-MMA graft polymer.

Polystyrene equivalent molecular weight by GPC is 11,000
(number average) and 63,000 (weight average).

Comparative Reference Example 1 Synthesis of styrene-MMA random polymer (11 Into the same apparatus as Reference Example 6, 10 parts of styrene, MM
Prepare 10 parts of A, 0.08 parts of dodecyl mercaptan, 10 parts of benzene, and 2 parts of ACH No. 80°C while introducing N.
The reaction was carried out for 15 hours.

The reaction solution was poured into 10 times the amount of n-hexane to cause precipitation, and then dried under reduced pressure at 80°C to obtain 115 parts of styrene-MMA random polymer.

Polystyrene equivalent molecular weight by GPC is 30,000
(number average) and 66.000 (weight average).

Comparative Reference Example 2 Synthesis of Styrene-MMA Random Polymer (2) A dumb polymer was synthesized to obtain 18.9 parts of the target product.

The polystyrene equivalent molecular weight by GPC is 89,000 (
number average) and 187.0'00 (weight average).

Examples 1-2 and Comparative Examples 1-3 Solution blending test>
Polystyrene (trade name: TOBOLEX GPPS50 D-51, manufactured by Mitsui Toatsu Chemical Co., Ltd., number average molecular weight approximately 60,000
), polyvinyl chloride (manufactured by Toagosei Chemical Industry Co., Ltd. Part name Aron PVCTS-700, number average molecular weight approximately 47.000
) were each dissolved in THF to prepare a 20% solution.

0.4 parts of various styrene-MMA copolymers synthesized in Reference Example 6.5 and Comparative Reference Examples 1 and 2 were added to 2 parts of polystyrene.
10 parts of 0% THF solution and 20% T of polyvinyl chloride)
It was placed in an Erlenmeyer flask together with 10 parts of the IP solution, and stirred for 60 minutes using a stirrer to dissolve and disperse. The cloudy, dispersed mixture solution was placed in a test tube to a liquid level of 8 crn. This was centrifuged (rotation speed: 2,000) and phase separation behavior was observed.

In this case, the centrifuge was stopped at 5 minutes, 15 minutes, 60 minutes, and 60 minutes of centrifugation, and the test tube was taken out and the temperature of the phase separation was examined to observe the change in phase separation over time. However, The volume of the phase-separated solution was taken to be the thermal degree of the phase = -------, X IDO (%), the total volume of the solution.The results were K as shown in Table 1 and Figure 1, and the compatibilization ability of the graft polymer was Proven.

3 4 Example 6 and Comparative Example 4 Polystyrene (trade name: TOBOLEX, GPPS500-51, manufactured by Mitsui Toatsu Chemical Co., Ltd.) and Bo! J-hinyl chloride (a compound containing a stabilizer and a lubricant in Aron PVcTS700 manufactured by Toagosei Chemical Co., Ltd.) was roll blended with a compatibilizer, and test pieces made from the blend were subjected to a tensile test and a Charpy impact test. . The results are shown in Table 2,
Furthermore, the tensile strength is shown in FIG. However, the test conditions are as follows.

Blending conditions 170°C, 5 minutes strength test O tensile test: according to JIS K7113, tensile speed 11
11 (/JEIX g).

0 Charpy impact test: Conducted according to JIS K7111.

As can be seen from Figure 2, the miscibility was improved by adding a few percent of the styrene-MMA graft polymer.
The tensile strength improved to a level approaching linearity for the blend composition.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the phase fraction heat of the compatibilizer in Examples 1 to 2 and Comparative Examples 1 to 3, and FIG. 2 is a graph showing a test prepared from the thermoplastic resin composition in Example 3 and Comparative Example 4. It is a graph showing the relationship between the tensile strength of a piece and the blend composition. 1...Comparative example 1 2...Example 1 3...#2 4...Comparative example 2 5...#3 Patent applicant Toagosei Chemical Industry Co., Ltd. Co., Ltd. 9 B 111 B duration (minutes)

Claims (1)

[Claims] 1. Thermoplastic resin made by blending 0.3 to 30 parts by weight of a styrene-methyl methacrylate graft polymer produced using a macromonomer to 100 parts by weight of a composition consisting of a polystyrene resin and a polyvinyl chloride resin. Composition.