JPH01254715A - Methacrylamide-based polymer - Google Patents

Abstract

PURPOSE:To provide the title copolymer outstanding in heat resistance, fluidity, coatability and resistance to discoloration, constituted of methacrylamide unit, styrene-based structural unit, (meth)acrylic acid unit and acrylic ester unit in specified proportion. CONSTITUTION:The objective copolymer 0.05-0.5 in specific viscosity (determined at 30 deg.C in the form of N,N-DMF solution with a concentration of 0.3g/100ml), a linear random copolymer constituted of (A) 5-60mol% of methacrylamide unit of formula I, (B) 35-90mol% of styrene-based structural unit of formula II (R<1>-R<3> are each H, Cl, etc.), (C) 0.1-2mol% of (meth)acrylic acid unit of formula III (R<4> is H or methyl), and (D) 0.1-20mol% of acrylic ester unit of formula IV (R<5> is 1-5C alkyl). A monomer corresponding to the structural unit of the formula II is pref. styrene. It is suggested that said copolymer be obtained by e.g., suspension copolymerization of the raw material monomers, normally at 30-250 deg.C for 0.5-16hrs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a methacrylamide copolymer having excellent heat resistance, fluidity, paintability and coloring resistance.

[Prior Art and its Problems] Polystyrene resin and acrylonitrile-styrene copolymer resin, which are known as general-purpose resins, have excellent moldability but low heat resistance.

Conventionally, as a method for improving the heat resistance of the above resins, monomers that increase heat resistance are copolymerized to produce styrene-maleic anhydride copolymers, styrene-methacrylic acid copolymers, and α-methylstyrene-acrylonitrile copolymers. There is a method of obtaining heat-resistant copolymers such as polymers. Although these methods have the effect of being able to improve heat resistance to some extent, the fluidity of the copolymer deteriorates due to the effects of hydrogen bonding of the carboxyl groups that the copolymer has in the molecule. There are problems such as decreased processability and coloration due to thermal decomposition of acrylonitrile.

In addition, when painting molded products, polystyrene resin has poor solvent resistance and low polarity, so the solvents that can be used are limited, and furthermore, complicated pretreatments such as roughening with a chromic acid mixture and introduction of active groups are required. There are issues such as the need for

[Problems to be Solved by the Invention] An object of the present invention is to eliminate such problems and provide a methacrylamide copolymer that has excellent heat resistance, fluidity, paintability, and color resistance.

[Means for Solving the Problems] That is, the present invention provides 5 to 60 mol% of methacrylamide units represented by the formula: , a chlorine group, a bromine group, or an alkyl group having 1 to 3 carbon atoms).
~90 mol%, 0.1 to 2 mol% of (meth)acrylic acid units represented by the formula: %formula% (in the formula, R4 represents a hydrogen group or a methyl group), and the formula: %formula% (in the formula , R5 represents an alkyl group having 1 to 5 carbon atoms), the linear random copolymer is composed of 0.1 to 20 mol% of acrylic acid ester units, and its specific viscosity (N
, in N-dimethylformamide solvent at a concentration of 0.3 g/
100 ml at a temperature of 30° C.) is 0.05 to 0.5.

[Example] The specific viscosity of the copolymer of the present invention is 0.05 to 0.5.

If the specific viscosity is less than 0.05, the molded product of the copolymer will deteriorate, and if it exceeds 0.5, the fluidity of the copolymer will be significantly reduced. The specific viscosity of the copolymer of the present invention was determined using an Ostwald viscometer at a concentration of 0.3 g/LOOml in N,N-dimethylformamide solvent, (N,N
-0.3 of the copolymer in LOOml of dimethylformamide
This is the value determined by A11l at a temperature of 30°C.

The proportion of methacrylamide units represented by the formula: % formula % in the methacrylamide copolymer of the present invention is 5 to 60 mol%.

The proportion of methacrylamide units in the copolymer is 5 mol%
If it is less than 1, the effect of improving the heat resistance of the copolymer is small,
Moreover, if it exceeds 60 mol%, the fluidity of the copolymer becomes significantly low.

Particularly preferably, the proportion of methacrylamide units in the copolymer is preferably 10 to 45 mol %, since this provides a practical balance between heat resistance and fluidity.

Formula in the methacrylamide copolymer of the present invention: (wherein,
R1, R2 and R3 are the same or different and each represents a hydrogen group, a chlorine group, a bromine group or an alkyl group having 1 to 3 carbon atoms) The proportion of styrene structural units is 35
~90 mol%. The styrene structural unit has the effect of improving the fluidity of the copolymer.

If the proportion of styrene structural units in the copolymer is less than 35 mol%, the fluidity of the copolymer is extremely low;
If it exceeds 0 mol%, heat resistance is low. In addition, examples of the styrene monomer providing the styrene structural unit in the present invention include styrene, orthochlorostyrene, parachlorostyrene, orthobromostyrene, parabromostyrene, orthomethylstyrene, paramethylstyrene, orthoethylstyrene. , paraethylstyrene, orthoisopropylstyrene, paraisopropylstyrene, 2
．． 4-dichlorostyrene, 2,6-dichlorostyrene,
2.4-dimethylstyrene, 2,4-diisopropylstyrene, 4-chloro-2-methylstyrene, 2.4.6
Examples include -1-dimethylstyrene, among which styrene is particularly preferred because of its monomer availability and cost advantages.

In the methacrylamide copolymer of the present invention, the proportion of (meth)acrylic acid units represented by the formula: % formula % (in the formula, R4 represents a hydrogen group or a methyl group) is 0.1 to 2 mol%.
It is.

By setting the proportion of (meth)acrylic acid units to 0.1 to 2 mol%, the coating properties are significantly improved. If the amount is more than 2 mol %, the effect of improving coating properties is small and fluidity is also reduced.

The proportion of acrylic ester units represented by the formula: % formula % (in the formula, R5 represents an alkyl group having 1 to 5 carbon atoms) in the methacrylamide copolymer of the present invention is 0.1 to 20
It is mole%.

When the proportion of acrylic acid ester units is 0.1 to 20 mol %, it has the effect of improving fluidity without significantly reducing heat resistance, and when it is more than 20 mol 26,
This is not preferred because the heat resistance is greatly reduced. Particularly preferably, the proportion of acrylic ester units in the copolymer is 1 to 10 mol % in view of the balance between heat resistance and fluidity.

The monomers constituting the methacrylamide copolymer of the present invention include the methacrylamide, styrene monomer, (
In addition to meth)acrylic acid and acrylic esters, monomers copolymerizable with them, such as maleic anhydride, N-phenylmaleimide, α-methylstyrene, (meth)acrylonitrile, and methyl methacrylate, can be used in the copolymer of the present invention. They can be used alone or in combination of 2 f'lf or more in a polymer to give a copolymerization ratio of 0 to 20 mol%.

If the above monomer is used as a constituent monomer of the copolymer,
Properties such as improved heat resistance can be imparted to the copolymer. However, if the copolymerization ratio of the monomer in the copolymer exceeds 20 mol %, the fluidity of the copolymer tends to decrease significantly.

The method of copolymerization in the present invention is not particularly limited, and includes ordinary suspension polymerization, emulsion polymerization, bulk polymerization,
A solution polymerization method etc. can be used.

During the reaction, benzoyl peroxide, tart-
Peroxides such as butyl peroxide, azo compounds such as 2,2'-azobisisobutyronitrile, 1,1'-azobis(1-cyclohexanecarbonitrile), potassium persulfate, ammonium persulfate, etc. Known initiators such as sulfides are preferably used. These initiators should be added in an amount of 0 to 3 parts by weight, especially <001 to 3 parts by weight, per 100 parts by weight of the monomers constituting the copolymer of the present invention, in order to improve the conversion rate and polymerization. Preferred because of its practicality in time balancing and molecular weight control.

Also, known organic dispersants such as methylcellulose and polyvinyl alcohol, inorganic dispersants such as tricalcium phosphate and magnesium phosphate, emulsifiers such as sodium valmitate, and surfactants such as sodium dodecylbenzenesulfonate can be used. Dispersants, emulsifiers and surfactants are optional additives for the purpose of uniformly dispersing the monomers and copolymers in a medium such as water. It is preferable to add 0 to 3 parts by weight, and preferably 0.01 to 3 parts by weight, per 100 parts by weight.

The reaction is usually carried out at 30-250°C for 0.5-16 hours.

In order to adjust the specific viscosity to the above-mentioned specific viscosity, known chain transfer agents such as Iert-dodecyl mercaptan and 2-mercaptoethanol, and known polyfunctional compounds such as diallyl phthalate, diethylene glycol diacrylate, and diethylene glycol dimethacrylate are used during the production of the copolymer. If necessary, 0 to 1 part by weight, and <0.01 to 1 part by weight, may be added to 100 parts by weight of the monomers constituting the copolymer of the present invention. , is preferable because it facilitates adjustment of specific viscosity.

Furthermore, known lubricants such as behenic acid, stearic acid, and liquid paraffin may be added to the methacrylamide copolymer of the present invention during the production of the copolymer, and monomers constituting the copolymer of the present invention may be added to the methacrylamide copolymer of the present invention. It is preferable to add 0 to 5 parts by weight, especially <0.1 to 5 parts by weight, based on a total of 100 parts by weight, since this improves the fluidity of the copolymer.

The copolymer obtained in the present invention may be used alone, and may be used in combination with the above-mentioned lubricants, known stabilizers such as 2,8-jert-butyl-4-methylphenol, colorants such as titanium oxide and red iron, and hexabromo. It may be used by blending it with a flame retardant such as benzene or other various polymers, and the amount is 0 to 5 parts by Ω per total polymerization of 100 parts of monomers constituting the copolymer of the present invention. It is preferable to add o, i to 5 parts by weight because it does not cause deterioration in processability and physical properties. Various polymers to be blended include polycarbonate resins such as polycarbonate obtained by the reaction of bisphenol A and phosgene, polyarylate resins such as polycondensation polymers of bisphenol A and phthalic acid, and polyamides such as nylon 6 and nylon 66. Engineering plastics such as vinyl chloride resins; vinyl chloride copolymer resins such as vinyl chloride homopolymers and vinyl chloride-vinyl acetate copolymers; chlorine content 5
Chlorinated vinyl chloride resin with a chlorine content of 8 to 70% by weight, MBS resin such as a graft copolymer obtained by grafting 20 to 80% by weight of styrene and methyl methacrylate to a diene rubber containing 50% by weight or more of butadiene, chlorine content 20
Chlorinated polyethylene resins such as ~50% by weight chlorinated polyethylene; acrylic rubber resins such as rubbers mainly composed of ethyl acrylate and butyl acrylate; random resins mainly composed of butadiene containing 820 to 50% by weight of acrylonitrile There are known resins such as Nt3R resins such as copolymers.

The copolymer of the present invention can be processed and molded using an injection molding machine, a roll molding machine, or an extrusion molding machine, and is used in the form of a plastic molded body, a foamed body, or the like.

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples.

Example 1 A monomer and di-tert-butyl peroxide as an initiator were charged into an autoclave having an internal volume of 3 g and equipped with a stirrer, adjusted to have the charging ratio shown in Table 1, and the autoclave was purged with nitrogen. The temperature inside the autoclave was raised to 120°C, and polymerization was carried out for 2 hours. Then heat to 240°C, 5 mm 11 g
After removing the remaining unreacted monomer under reduced pressure, the copolymer was taken out from the bottom of the autoclave.

Elemental analyzer CHN- manufactured by Hcracos
Methacrylamide units in the copolymer obtained by elemental analysis and nuclear magnetic resonance using 0-Rapid,
The proportions of styrene structural units, (meth)acrylic acid units and acrylic acid ester units, that is, the copolymerization ratio of each single unit in the obtained copolymer, were measured. The result is the first
Shown in the table.

In addition, the specific viscosity of the obtained copolymer was measured using an Ostwald viscometer in an N,N-dimethylformamide solvent at a concentration of 0.
．． Measured at 3 g/LOOml and a temperature of 30°C. The results are shown in Table 1.

Further, test pieces having dimensions corresponding to each measurement were molded from the obtained copolymer using an injection molding machine (manufactured by Nisshin Jushi Kogyo ■, FS-150) with a mold clamping cuff of 5 tons.

Using the test piece, the heat resistance, fluidity, paintability, and color resistance of the obtained copolymer were determined according to the following methods. The results are shown in Table 1.

(Heat resistance) According to the test method specified in JISK 720B,
Using a test piece of 20mm x 20+nm x 3+nm, the Vicat softening temperature was measured using a Vicat softening temperature tester (YSS Tester, manufactured by Kakushi Seisakusho) under a load of 5 kg/cd, and the heat resistance was judged as a criterion. did.

If the Vicat softening temperature is 105° C. or higher, it is practical.

(Fluidity) According to the test method specified in JIS K 7210, a pellet-shaped test piece was used and an extrusion plastometer (Flow Tester, NT-3, manufactured by Shimadzu Corporation) was used at a load of 100 kg/cd and a measurement temperature of 240°C. The volume of the sample extruded in 1 second by method B flow under the conditions of ℃ was measured and used as a criterion for fluidity.

(Paintability) Acrylic lacquer (red, made by Natco Paint ■, Natco 8) was sprayed on a test piece measuring 70 mm x 70 mm x 3 mm, and then heated at 23°C, relative humidity 5.
The sample was left in a constant temperature room at 0% temperature for 72 hours to dry.

A cut was made in the test piece according to the base grain test method specified in JIS K 5400. Next, Cellotape CT-24 (manufactured by Chiban ■) was adhered to the cellophane adhesive tape so as not to form air bubbles on the substrate, and then the cellophane adhesive tape was peeled off. This operation was performed once in two directions, vertically and horizontally, and the state of peeling of the coating film was examined.

The evaluation score is divided into 6 levels: 0, 2.4.6.8.10.
Each evaluation score was based on the determination content of JIS K 5400. For paintability, a score of 10 is the best.

(Coloring resistance) Judging by visual inspection of a 3 mm thick test piece,
Color resistance was evaluated according to the following criteria.

(Judgment criteria) O: Almost no coloring.

△: Very light yellow coloring.

×: Yellow coloring present.

In terms of appearance, those marked O and Δ can be practically used.

Examples 2 and 3 and Comparative Examples 1 and 2 In Example 1, the same method as in Example 1 was used except that the amount of the initiator di-tGrt-butyl peroxide was adjusted as shown in Table 1. Therefore, a copolymer was obtained. The copolymerization ratio of monomers in the obtained copolymer was measured in the same manner as in Example 1. The results are shown in Table 1. In addition, the specific viscosity and physical properties of the obtained copolymer, such as heat resistance, fluidity, paintability, and color resistance, were determined in the same manner as in Example 1.

The results are shown in Table 1.

Examples 4 to 11 and Comparative Examples 3 to 8 In Example 1, the monomer charging ratio was adjusted as shown in Table 1, and the blending amount of the initiator di-1 crt-butyl peroxide was 0.10% by weight. A copolymer was obtained in the same manner as in Example 1 except that The copolymerization ratio of the monomers in the obtained copolymer was determined as 4111 in the same manner as in Example 1. The results are shown in Table 1. In addition, the specific viscosity and physical properties of the resulting copolymer include heat resistance,
Fluidity, paintability and coloring resistance were determined in the same manner as in Example 1. The results are shown in Table 1.

Examples 12 to 17 In Example 1, the styrenic monomer shown in Table 2 was used instead of styrene, and the initiator G-78rt
A copolymer was obtained in the same manner as in Example 1, except that the amount of -butyl peroxide was changed to the amount shown in Table 2. The copolymerization ratio of monomers in the obtained copolymer was measured in the same manner as in Example 1. The results are shown in Table 2. Further, the specific viscosity and physical properties of the obtained copolymer, such as heat resistance, fluidity, paintability, and color resistance, were determined in the same manner as in Example 1. The results are shown in Table 2.

As is clear from Table 1, in Comparative Example 1, the specific viscosity was 0.03, less than 0.05, so the copolymer molded product was brittle and it was not possible to form a test piece. . In Comparative Example 2, the specific viscosity exceeded 0.5 and was 0.58, so the fluidity was significantly lower than in Examples 1 to 3, and molding could not be performed. In Comparative Example 3, the copolymerization ratio of methacrylamide in the copolymer was 3.0 mol%, which was less than 5 mol%, so the heat resistance of the copolymer was as low as 95°C, and in Comparative Example 4, Since the copolymerization ratio of methacrylamide in the copolymer exceeded 60 mol% and was 67.8 mol%, the copolymer decomposed during molding, and therefore a test piece could not be produced. Furthermore, in Comparative Example 5, the copolymerization ratio of (meth)acrylic acid in the copolymer was 0 mol%, so the paintability of the copolymer was one rank lower. Since the copolymerization ratio of methacrylic acid exceeds 2 mol% and is 10 mol%,
The fluidity was significantly lower than that of Example 9. In Comparative Example 7, the copolymerization ratio of acrylic acid ester in the copolymer exceeded 20 mol% and was 25 mol%, so the heat resistance was significantly lower than in Example 11. Comparative example 8
Crazing occurred due to the poor solvent resistance of polystyrene.

[Effects of the Invention] The methacrylamide copolymer of the present invention has excellent heat resistance, fluidity, paintability, and diluted color resistance, so it can be used for various injection molded products, extrusion foam molded products, and coating substrates, etc. It has the effect of a vine.

Patent applicant Kanebuchi Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1 Formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ 5 to 60 mol% of methacrylamide units, formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 , R^2 and R^3 are the same or different and each has a hydrogen group, a chlorine group, a bromine group, or a carbon number of 1 to
35 to 90 mol% of styrenic structural units represented by (indicates the alkyl group of 3), formula: ▲ There are mathematical formulas, chemical formulas, tables, etc. 0.1 to 2 mol% of (meth)acrylic acid units, and the formula: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^5 represents an alkyl group having 1 to 5 carbon atoms) Acrylic acid ester unit 0.1-20 mol%
A linear random copolymer consisting of
In N,N-dimethylformamide solvent, concentration 0.3 g/
A methacrylamide-based copolymer having a temperature of 0.05 to 0.5 (measured at 100 ml and a temperature of 30°C). 2 The proportion of methacrylamide units in the copolymer is 10 to
The methacrylamide copolymer according to claim 1, which has a content of 45 mol%. 3. The methacrylamide copolymer according to claim 1 or 2, wherein the monomer providing the styrene structural unit is styrene.