JPS63152610A - Stabilization of diene based polymer - Google Patents

Abstract

PURPOSE:To produce a diene based polymer having excellent weather resistance, by copolymer a specific amount of a specified piperidine compound in polymerizing the diene based polymer. CONSTITUTION:A diene based polymer obtained by polymerizing a monomer, containing a conjugated diene compound, e.g. butadiene, ethylidenenorbornene, etc., as an essential component and having polymerizable unsaturated double bond is stabilized. In the process, a piperidine compound, e.g. 2,2,6,6- tetramethyl-4-piperidyl acrylate, etc., expressed by formula I [R is H, alkyl or acyl; R1 is H or CH3; X is =CH- or formula II (R2 is lower alkyl), in an amount of 0.001-30wt% based on the total monomer is copolymerized in producing the above-mentioned diene based polymer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for stabilizing a diene polymer, specifically, a method for stabilizing a diene polymer obtained by copolymerizing a conjugated diene compound with a specific piperidine compound. Regarding the conversion method.

[Conventional technology and its problems]

Synthetic rubber latex, represented by styrene-butadiene latex, is used as a binder for paper coating, as a car vent,
It is used in a wide range of applications, including banking binders, asbestos binders, cement mortar admixtures, paints, adhesives, and adhesives.

In addition, thermoplastic elastomers, which are copolymers of conjugated dienes and vinyl aromatic compounds, are used in resin modifiers, asphalt modifiers, adhesives, footwear, various molded articles, other industrial products, miscellaneous goods, etc. has been done.

Furthermore, impact-resistant resins containing diene polymers, such as ABS resins, have many uses as plastic molded products.

However, because diene polymers have chemically active double bonds remaining in their main chains, they are easily oxidized by oxygen in the air. This tendency is promoted as the temperature increases. Also, as a matter of course, it is easily affected by ultraviolet rays,
The action of sunlight not only causes rapid yellowing, but also causes crosslinking and decomposition, leading to a decline in the physical properties of the polymer.

These physical properties are fatal drawbacks in fields where durability is required, and limit the uses of diene polymers. For this purpose, various methods have been studied in the past. As a result, various effective anti-aging agents have been developed to improve heat resistance, and practical heat resistance has been achieved. However, although studies on improving light resistance have been made over the past many years, it has not yet reached a practical level.

For example, Japanese Patent Publication No. 57-57058 discloses a method of blending an ultraviolet absorber into ABS resin, and JP-A No. 58-352.
No. 21 discloses a method of blending benzophenone-based or benzotriazole-based ultraviolet absorbers, 2,2,6,6-titramethylpiperidine derivatives, and phosphoryl triamide with ABS resin, and JP-A-59-53545 discloses ,
Method for blending titanium dioxide and hindered amine light stabilizer into synthetic rubber latex, JP-A-60-72953
JP-A-60-108458 discloses a method of blending a conjugated diene-vinyl aromatic hydrocarbon block copolymer with a higher fatty acid and a hindered amine compound, and JP-A-60-108458 describes a method of blending a conjugated diene-vinyl aromatic hydrocarbon block copolymer with a process oil and a hindered amine compound. Alternatively, a method of blending a benzotriazole compound is disclosed. however,
Although these methods slightly improve the weather resistance and discoloration resistance of diene polymers, they have not yet reached a level that is satisfactory from a practical standpoint.

Note that Japanese Patent Publication No. 47-8539 describes that a piperidine compound having an acryloyl group is a deterioration inhibitor for polymeric materials, and also describes that the compound can be copolymerized with raw material monomers. However, there is no mention of copolymerization with diene compounds.

[Means for solving problems]

As a result of extensive research into improving the weather resistance of diene polymers, the present inventors have discovered that by copolymerizing a specific reactive piperidine compound during the polymerization of diene polymers, they have achieved weather resistance that cannot be obtained by conventional methods. They discovered that a diene polymer with excellent properties can be obtained, and completed the present invention.

That is, the present invention is a method for stabilizing a diene polymer obtained by polymerizing a monomer having a polymerizable unsaturated double bond and containing a conjugated diene compound as an essential component,
When manufacturing a cough diene polymer, 0.0% is added to all monomers.
The present invention provides a method for stabilizing a diene polymer, which comprises copolymerizing 001 to 30% by weight of a piperidine compound represented by the following general formula (I).

(In the formula, R represents a hydrogen atom, an alkyl group, or an acyl group, R1 represents a hydrogen atom or a methyl group, represents X, and R2
represents a lower alkyl group. ) Hereinafter, the method for stabilizing the diene polymer of the present invention will be described in detail.

Examples of the conjugated diene compound used in the present invention include butadiene, isoprene, chlorobrene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1.
Examples include 3-hexadiene, ethylidenenorbornene, dicyclopentadiene, and particularly common examples include butadiene and isoprene. These are 1
Not only seeds but also a mixture of two or more types may be used, and
These conjugated diene compounds can be copolymerized with a copolymerizable ethylenically unsaturated monomer. Examples of these ethylenically unsaturated monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, and divinylbenzene; methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate,
Acrylic acid alkyl esters such as 2-ethylhexyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and octyl methacrylate; acrylonitrile, vinylidene chloride, vinyl chloride, vinyl acetate, and the like. Furthermore, a vinyl monomer having a functional group can also be used, and such vinyl monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and fumaric acid; β-hydroxyethyl acrylate, hydroxypropyl acrylate, etc. Hydroxyalkyl methacrylates such as; vinyl compounds having a glycidyl group such as glycidyl methacrylate and glycidyl acrylate; compounds having an amide group such as niacrylamide and N-methylolacrylamide;

Therefore, examples of diene-based (co)polymers stabilized by the piperidine compound of the present invention include, for example, styrene-
Butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylonitrile-butadiene copolymer, vinylidene chloride-styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-propylene-ethylidene norbornene copolymer, etc. can be mentioned.

Further, in the piperidine compound represented by the general formula (I), examples of the alkyl group represented by R include methyl, ethyl, propyl, butyl, isobutyl, octyl, etc., and examples of the acyl group include acetyl, propionyl, butyroyl. , acryloyl, methacryloyl, etc.

Therefore, representative examples of the piperidine compound represented by the general formula (I) used in the present invention include the following compounds.

Magnetic 12.2,6.6-Titramethyl-4-piperidyl acrylate Magnetic 22.2.6.6-Titramethyl-4-piperidyl methacrylate Positive 3 1,2,2,6.6-bentamethyl-4-piperidyl acrylate Magnetic 4 1,2 .2,6,6-bentamethyl-4-piperidyl methacrylate 51-acetyl-2,2,6,6-tetramethyl-4
-piperidyl meccrylate 69-aza-3-ethyl-8,8,to, 10-tetramethyl-1,5-dioxaspiro[5,5]-3-undecylmethyl acrylate 79-aza-3-ethyl -8,8,10,10-tetramethyl-1,5-dio-xaspiro(5,5)-3-
Undecylmethyl methacrylate-89-aza-3-ethyl-8,8,9,10,10-
Pentamethyl-1,5-dioxaspiro(5,5)-3
-Undecyl methyl acrylate Note that the diene polymer obtained in the present invention may contain commonly used additives, such as heat stabilizers, lubricants, softening agents, antioxidants, and light stabilizers, as necessary. , fillers, antistatic agents,
Antifoaming agents, bactericidal agents, dispersants, thickeners, softeners, etc. can be appropriately added.

(Examples) The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples. In the Examples, "parts" indicate "parts by weight."

Example 1 First, 100 parts of water, 0.2 parts of sodium dodecylbenzenesulfonate, 3 parts of seed latex (styrene/butadiene = 70/30 copolymer latex), and sodium ethylenediaminetetraacetate were placed in a pressure-resistant polymerization vessel equipped with a dropping device and a stirrer. 0.05 parts of sodium persulfate, 2 parts of sodium persulfate, and 0.2 parts of sodium hydroxide, then 47 parts of styrene, 1.
50 parts of 3-butadiene, 3 parts of acrylic acid, 0.3 parts of light stabilizer (see Table 1 below), and 0.7 parts of t-dodecylmercaptan were charged, and after thorough nitrogen purging, the mixture was heated to 90°C. The mixture was allowed to react for 6 hours. As a result, a latex with a solid content of 50% was obtained. The pH of the obtained latex was adjusted to 8.0 with an aqueous sodium hydroxide solution, and then steam and nitrogen blowing was performed to remove residual monomers. Next, 1 part of a 50% aqueous dispersion of stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added to 100 parts of the solid content of this latex.

This latex is applied onto a polyester film, and -
After air drying at night, dry at 100℃ for 30 minutes to a thickness of 0.5 t.
I created a sheet for s. This sheet was irradiated with ultraviolet rays using a high-pressure mercury lamp, and the yellowness of the sheet was measured over time. The results are shown in Table 1 below.

Table-1 *1: Not added during polymerization, but added after latex production.

Example 2 Using the same reaction apparatus as in Example 1, under a nitrogen gas atmosphere,
n- containing 15 parts l,3-butadiene and 20 parts styrene
Add 0.11 parts of n-butyllithium to the hexane solution, polymerize at 70°C for 2 hours, and then add 45 parts of 1.3-butadiene, 20 parts of styrene, and 0.5 parts of light stabilizer (see Table 2 below). A solution containing n-hexane containing 30% was added thereto, and polymerization was carried out at 70°C for 2 hours. In the obtained block copolymer, BHT and tris(nonylphenyl)phosphite were added as stabilizers at 0.5 parts each per 100 parts of the block copolymer.
Part was added. Weather resistance and color tone were investigated using compression molded pieces of the block copolymer composition. The results are shown in Table 2 below.

Weather resistance was evaluated by measuring the tensile strength of each sample after 150 hours of irradiation with a sunshine weather meter, and judging the quality based on the retention rate.

Table-2 *1: Not added during polymerization, but added together with a stabilizer.

Judgment criteria A: Retention rate 80% or more B: Retention rate 60% or more, less than 80% C; Retention rate 40% or more, less than 60% D: Retention rate less than 40% Example 3 30 parts of styrene under nitrogen gas atmosphere Add 0.35 parts of n-butyllithium to the cyclohexane solution containing
After polymerizing at 70°C for 1 hour, a cyclohexane solution containing 70 parts of 1,3-butadiene and 0.5 parts of a light stabilizer (see Table 3 below) was added, and polymerization was performed at 70°C for 2 hours. Then, tetrachlorosilane was added to the A of the n-butyllithium used.
An equivalent amount was added and treated to obtain a block copolymer. BHT and tris(nonylphenyl)phosphite were added to the block copolymer 1 as a stabilizer to the obtained block copolymer.
Each was added in an amount of 0.5 parts per 00 parts.

Example 2 using compression molded pieces of block copolymer composition
Weather resistance and color tone were examined in the same manner as above. The results are shown in Table 3 below.

Table-3 *1: Not added during polymerization, but added together with a stabilizer.

Judgment criteria: Same as Example 2.

Example 4 Polybutadiene latex (rubber concentration 50%) was placed in the reaction vessel.
) 40 parts, 72 parts of styrene, 28 parts of acrylonitrile,
Add 150 parts of water in which 0.5 parts of light stabilizer (see Table 4 below), 0.6 parts of t-dodecyl mercaptan and 2 parts of disproportionated sodium rosinate were dissolved, and the temperature was raised to 60°C. 0.5 part of potassium persulfate was dissolved at the temperature. 20 parts of water were added over 3 hours. Polymerization was further carried out at 60°C for 3 hours. Hydrochloric acid was added to the resulting graft copolymer, the mixture was heated to coagulate, washed with water, and then dried. The resulting graft copolymer contained 0.2 parts of stearyl-β-(3,5-di-tertiary) as a stabilizer per 100 parts of the graft copolymer.
Butyl-4-hydroxyphenyl)propionate was added. Weather resistance and color tone were investigated using injection molded pieces of the graft copolymer.

The results are shown in Table 4 below.

Weather resistance was evaluated by measuring the tensile strength and impact strength of each sample after 400 hours of irradiation with a sunshine weather meter, and judging the quality based on the retention rate.

Table-4 *1: Not added during polymerization, but added together with a stabilizer.

Judgment criteria A: Retention rate 95% or more B: Retention rate 90% or more, less than 95% C: Retention rate 85% or more, less than 90% D: Retention rate less than 85% Example 5 Polybutadiene latex of Example 4 instead of styrene-butadiene copolymer latex (styrene-containing 1t
25%, rubber concentration 50%) were all used in Example 4.
A graft copolymer was prepared under the same conditions. Graft copolymer 10 was added to the obtained graft copolymer as a stabilizer.
0 parts of stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate was added. Weather resistance and color tone were examined in the same manner as in Example 4 using an injection molded piece of the graft copolymer. The results are shown in Table 5 below.

Table-5 *1: Not added during polymerization, but added together with a stabilizer.

Judgment criteria: Same as Example 4.

〔Effect of the invention〕

According to the method for stabilizing a diene polymer of the present invention, a diene polymer with excellent weather resistance that cannot be obtained by conventional methods can be obtained.

Claims (1)

[Scope of Claims] A method for stabilizing a diene polymer obtained by polymerizing a monomer having a polymerizable unsaturated double bond and containing a conjugated diene compound as an essential component, the method comprising: A method for stabilizing a diene polymer, which comprises copolymerizing a piperidine compound represented by the following general formula (I) in an amount of 0.001 to 30% by weight based on the total monomers during production. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R represents a hydrogen atom, an alkyl group, or an acyl group, R_1 represents a hydrogen atom or a methyl group, and X represents >CH-
Or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R_2
represents a lower alkyl group. )