JPS5928335B2 - Internally plasticized vinyl chloride copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to internally circularly plasticized copolymers of vinyl chloride, alkyl, acrylates, and bis(hydrocarbyl)vinylphosphonates.

For the desired purpose, external plasticizers are commonly incorporated into vinyl chloride homopolymers and copolymers to obtain products with desired flexibility.

However, such external plasticizers are not fully satisfactory because the plasticizers tend to micrate on the surface and are lost by evaporation or extraction. . The loss of such plasticizers can lead to hardening of surfaces, fogging of automobile windshields, and weakening of vinyl films containing polymers used in shower curtains, diaper covers, vinyl seat covers, etc. Cow the problem. Various proposals have been made for internal plasticization of vinyl chloride polymers. The plasticizing action is accomplished by providing one or more comonomers that copolymerize with vinyl chloride to form a polymer. vinyl
The use of copolymers of vinylesters of monomers and polymerized polyesters such as acrylates or polyesters of aliphatic hydrodicarboxylic acids is disclosed in U.S. Pat. No. 3,640,9
No. 27 (C.S. Marveltal).

Vinyl chloride component approximately 75 to 95 weight? , for example C6~C
about 2 ester components of unsaturated mono- or polycarboxylic acids such as l2 alkyl maleates, fumarates or acrylates;
5-5 weight? A two-component vinyl chloride copolymer with internal circular plasticization is disclosed in U.S. Pat.
etc.). U.S. Pat. No. 3,196,133 (R.A.P.
ilOni et al.). The four-component polymer composition has excellent adhesiveness and flexibility and is used as a coating agent using a solvent. Currently pending U.S. patent application Ser. Consolidation is described. Binary copolymers of vinyl chloride and acrylates, such as 2-ethylhexyl acrylate, are disclosed in U.S. Pat.
No. 544,661, a heterogeneous resin composition is produced, and such composition does not have the desirable characteristics of the flexible vinyl film of the present invention.

Vinyl chloride/vinyl phosphonate two-component copolymers are
It is well known that the copolymerization of vinyl chloride and bis(hydrocarbyl) vinylphosphonates, such as bis(beta chloroethyl) vinylphosphonate, produces stiff, relatively low deflection films that require external plasticization. and are not classified as internal plasticized copolymers because they require an external plasticizer (U.S. Pat. No. 3,691,127, 3,7
No. 92,113 and No. 3,819,770).

The vinyl chloride/acrylate/vinyl phosphonate copolymers described herein have properties comparable in many respects to external plasticized polyvinyl chloride without the addition of substantial amounts of external plasticizer. was unknown until today. As shown in conventionally known patents, the appearance and The property becomes something completely different. Additionally, the terpolymer reduces fuming. The copolymers of the present invention contain about 50-85% by weight of a vinyl chloride component, about 3-47% by weight of a C6-C, O2 acrylate component such as 2-ethylhexyl acrylate, and about 3-47% by weight of a vinyl chloride component such as 2-ethylhexyl acrylate. Bis(hydrocarbyl)vinylphosphonate component approximately 3-47% by weight? is a plasticized vinyl chloride copolymer with

The copolymer can be produced by known suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization methods, and can be used in fields where plasticized polyvinyl chloride is used, such as vinyl films or sheeting materials, vinyl wire and cable insulation. It can be used as wood, vinyl flooring, and bags and tubes for rotating equipment. The flexible vinyl film produced from the internally plasticized vinyl chloride copolymer of the present invention has a crush value of about 0 without externally plasticizing.
℃ or below, preferably -15℃ or below, the tensile strength at break has been found to be about 60 kg/i or above, preferably about 80 k9/(711 or above). The polymer can be prepared by a known emulsion polymerization, suspension polymerization, bulk polymerization or solution polymerization method, and a specific amount of vinyl chloride, C6-C, alkyl acrylate, bis(
It is prepared using a basic ternary monomer with a bis(hydrocarbyl)vinylphosphonate such as beta-chloroethyl)vinylphosphonate. For more details,
The present invention uses vinyl chloride, about 50-80% by weight, C6-Cl
O al o acrylate weight about 3~47? , bis(hydrocarbyl)vinylphosphonate approximately 3-47% by weight? It is an internally circularly plasticized copolymer copolymerized with The term 1bis(hydrocarbyl)vinylphosphonevi used in the present invention has the general formula (where X is hydrogen, halogen, cyano group,
Aryl groups such as phenyl, C1-C,8 alkyl groups, and general formulas where R and R'' are hydrocarbyl and substituted hydrocarbyl groups consisting essentially of hydrogen atoms and carbon atoms and having up to 18 carbon atoms; ' are the same or different, or R and R' combine to form one group.

) refers to vinyl phosphonates represented by As used herein, the expression zero hydrocarbyl and substituted hydrocarbyl groups in the definition of suitable bis(hydrocarbyl)vinylphosphonates above refers to the removal of hydrogen from either aliphatic or aromatic hydrocarbon or substituted hydrocarbon groups. It means a group obtained by
These hydrocarbyl groups may be substituted by any group that does not interfere with the polymerization of the bis(hydrocarbyl)vinylphosphonate. Such substituents include chloro, bromo, fluoro, nitro hydroxy, sulfonate, ethoxy, methoxy,
Examples include nitriles, ether esters and keto groups. Examples of aliphatic and aromatic groups represented by R and R' in the structure of bis(hydrocarbyl)vinylphosphonate above are methyl ethyl propyl SSSS butyl
Alkyl groups such as pentyl, hexyl, and nonyl groups; alkenyl groups such as pentenyl, hexyl groups, and their isocyl groups; cycloγ alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups; cyclohexenyl groups and representative allyl groups such as phenyl, benzyl, phenethyl, tolyl, and naphthyl groups.

Representative examples of the above bis(hydrocarbyl)vinyl phosphonates are listed below.

Bis(betachloroethyl)vinylphosphonate; bis(2-ethylhexyl)vinylphosphonate; bis(
Betachloropropyl) vinylphosphonate; bis(
Bis(beta chloroethyl) 1-methylvinylphosphonate; Bis(beta chloroethyl) 1-cynovinylphosphonate; Bis(beta chloroethyl) 1-chlorovinylphosphonate; Bis(beta chloroethyl) 1-
Phenyl vinyl phosphonate; dimethyl vinyl phosphonate; diethyl vinyl phosphonate; bis(omega-chlorobutyl) vinyl phosphonate; di-n-butyl vinyl phosphonate; diisobutyl vinyl phosphonate; bis(2-chloroisopropyl) 1-methyl vinyl phosphonate; diphenyl vinyl phosphonate; and bis(2,3-dibromopropyl)vinylphosphonate.

Among the above-mentioned bis(hydrocarbyl)vinylphosphonate monomers, bis(beta-chloroethyl)vinylphosphonate is preferably used for producing the novel copolymers of the present invention.

Bis(beta-chloroethyl)vinylphosphonate is readily available and less expensive than any of the other bis(hydrocarbyl)vinylphosphonates. Bis(2-ethylhexyl)vinylphosphonate is also a preferred monomer because of its ability to produce products with desirable physical properties such as flexibility retention at low temperatures. Representative C6-C10 alkyl acrylates that may be used in the practice of this invention include n-helyl acrylate, cyclohexyl acrylate, n-octyl acrylate, 2-octyl acrylate,
These are ethylhexyl acrylate and mixtures of the above acrylates.

It is preferable to use the C8-C10 aluminum acrylates. In particular, branched gamma alkyl groups provide good enclosure to the resins produced. If desired, mixtures of each gamma alkyl acrylate and vinyl phosphonate may be used.

From a cost and performance standpoint, a preferred copolymer has a vinyl chloride component of about 55-80% and a C6-C10 acrylate component of about 10-35% by weight. , screw (C2-C8
(alkyl) or (C, ~C8 haloalyl) vinylphosphonate component about 5 to 25% by weight? It is a terpolymer copolymerized with Terpolymers that can be used to produce films having a Shore "A" hardness of approximately 60 to 70 include approximately 56 to 58% by weight of vinyl chloride component, approximately 29 to 31% by weight of 2-ethylhexyl acrylate component, and bis(beta). chloroethyl) vinylphosphonate, or bis(2-ethylhexyl) vinylphosphonate.
A terpolymer having a hardness of about 85 to 95 has a vinyl chloride component of about 73 to 75% by weight, a C6 to C,0 alkyl gamma acrylate component such as 2-ethylhexyl acrylate of about 17 to 19% by weight, and a vinyl chloride component of about 17 to 19% by weight. Bis(hydrocarbyls) such as (beta chloroethyl) vinylphosphonate
It has a vinyl phosphonate component of about 7-9% by weight. The copolymer of the present invention is produced by known bulk polymerization, emulsion polymerization, suspension polymerization, and solution polymerization methods.

According to the suspension polymerization method, the product can be easily separated from the latex, the heat of reaction can be easily removed compared to the bulk polymerization method, and the problem of recovering the solvent required in the solution polymerization method can be avoided. Therefore, the suspension polymerization method is preferred. The suspension polymerization reaction mixture contains about 20 to 45% by weight of the monomers listed above, based on the amount of water, in the aqueous reaction medium.

Also, the amount of suspending agent such as methyl cellulose, hydroxypropyl methyl cellulose, gelatin, etc. is about 0.0% based on the weight of the monomer. O5-5% by weight; based on the monomer weight,
At least one monomer solution initiator, such as azobisisobutyronitrile, lauroyl peroxide, benzoyl peroxide, or isopropyl peroxydicarbonate, contains about 0.0
05 to 1% by weight. The polymerization reaction of the suspension containing the above components is carried out at a temperature of about 35 DEG C. to 75 DEG C. for about 2 to 12 hours, with sufficient stirring during the reaction. As is known in the literature, when using initiators with high activity among the above initiators, lower temperatures and/or shorter reaction times are used, and when initiators with lower activity range are used. may require more aggressive reaction conditions. If desired, an effective amount of a chain transfer agent can be added during the polymerization to control the molecular weight of the polymers. The agent is usually about 0.01-0.1% based on the weight of the monomer.
is valid. Typical chain transfer agents are chlorinated hydrocarbons such as tetrachloroethane, trichloroethane, carbon tetrachloride; and common RSH (where R is a 1γ group such as a C1-{12 alkyl group such as butyl or dodecyl); mercaptans (representing a group). If the emulsion polymerization method is used, the above suspending agent is mixed with about 0.2 to 2 weight of emulsifier such as sodium lauryl sulfate, potassium stearate, alkyl benzene sulfonate, dialkyl ammonium sulfosuccinate, etc. Replace it with
The monomer solution initiator may be a metal persulfate, a perborate, or an ammonium salt of peracetic acid, persulfuric acid, perboric acid, or peracetic acid, urea peroxide, hydrogen peroxide, t-butyl hydroperoxide. Approximately 0.1 to 1 weight? This can be implemented by replacing with .

ammonium persulfate, sodium hydrogen sulfate, if desired;
Alternatively, redox initiators such as hydrogen peroxide and ascorbic acid can also be used as initiators. When carrying out bulk polymerization, the monomers can be suspended in the presence of the above-mentioned amount of molten monomer catalyst and copolymerized at the same temperature and for the same time as in emulsion polymerization.

When performing the solution polymerization method, butane, pentane octane, benzene, toluene, cyclohexanone, acetone,
The monomers are polymerized in the presence of at least one inert organic solvent such as isopropanol or tetrahydrofuran.

The initiator chosen must be soluble in the reaction medium. At the end of the copolymerization, the copolymer can remain dissolved in the solvent, or it can be precipitated from the liquid phase during the copolymerization. In the former case, the produced copolymer can be obtained by evaporating the solvent or by precipitating it by adding a non-solvent of the bovine product. The same reaction conditions used for suspension polymerization and emulsion polymerization can be used. The final product of the invention can be formulated with any desired additives that are compatible with the copolymer and have no adverse effects.

Additives 1 of this type include heat stabilizers, light stabilizers, UV stabilizers, pigments, fillers, dyes and other additives known to those skilled in the art. Those skilled in the art can also select and use additives as appropriate from the list of additives described in Modern Plastics Encyclopedia, Vol. 5L, 10A, pages 1735-754. The following examples are provided to further illustrate preferred embodiments of the invention.

Example 1 This example describes a general method for producing Uchimachi plasticized resin according to the method of the present invention by suspension polymerization.

The following ingredients were used.

All amounts are shown in parts by weight. The vinyl chloride acrylate and vinyl phosphonate monomers were polymerized by the method described below.

1. The suspending agent was dissolved in a portion of pure water and charged into the reactor together with the remaining pure water.

The mixture was stirred briefly to dissolve the polymerization initiator solution of peroxycarbonate and heptane. 2. The acrylate and vinyl phosphonate monomers were added.

3. The reactor was closed and vacuum applied (approximately 584.2 to 635
Remove the air as a vacuum degree of mmHg and remove the vinyl chloride.
The monomer was added so that vacuum was lost.

The operation was repeated once more and vinyl chloride was introduced into the reactor. 4. Adjust the stirrer to 496 rpm, heat the reactor to 50°C, and increase the pressure from the highest pressure at the start of the reaction to 4.2
The reactor pressure was reduced by k9/Crli.

A reactor with an internal volume of 5.44 liters was evacuated and nitrogen gas was introduced at a rate of 70.7 (1-71/sec) for 1 hour.
The residual monomer was removed from the product.

6. The reactor was cooled, the polymer particles were collected by centrifugation, and the particles were dried in a fluidized bed with air at 30°C.

7. The dried polymer was ground in a Fitz mill and sieved through a 30 mesh sieve.

The above method was repeated three times.

The resulting polymer contained about 57.4-57.7% by weight of vinyl chloride component and about 29.7-31.5% by weight. 2-ethyl-acrylate component and about 11.1 to 12,6
% bis(β-chloroethyl)vinylphosphonate component, and had a specific viscosity of about 2.74 to 3.07 when measured as a 1% solution in cyclohexane. In either case, the supplied mixture contained the above monomers in a ratio of 60:28:12 by weight. It was blended in the following proportions.

The differences were due to slight uncontrollable changes in the reaction conditions mentioned above. Example 2 This example illustrates the closure of various film compositions made from the copolymers of the present invention.

Tests were conducted using the following test samples.

Samples 1 to 3: Sample compressible film compositions were prepared by mixing the following components in the following amounts.

The ingredients listed in the above composition were mixed and sample 1 was 1
Processed in a diroll mill with dirolls heated to 54°C and 157°C, respectively; Samples 2 and 3 were heated to 157°C.
and treated at 160°C.

After fluxing in a two-roll mill for about 7 minutes, the composition was compression molded at 160°C to a thickness of 0.09mm. to 0.
12cIr1 films were prepared and the circumference was measured by various standard test methods.

Samples 4 to 7 Compressible film compositions for samples were prepared by mixing the following components in the following amounts.

The milling conditions were the same for samples 4 and 5 (and sample 1), and the same for samples 6 and 7 as for samples 2 and 3.

Samples 8 to 11: Sample compressible film compositions were prepared by mixing the following components in the following amounts.

The same is true for samples 9 to 11. This is the same as for samples 2 and 3.

Samples 12 to 13 Compressible film compositions for samples were prepared by mixing the following components in the following amounts.

Samples 1 to 3 using the Uchimachi plasticized resin of the present invention showed almost the same properties.

The resin for Sample 3 was somewhat softer than the resins for Samples 1 and 2. Samples 4 to 7 show the effect of adding an epoxy stabilizer to Samples 1 and 2. When epoxidized octyl tarate was used at a ratio of 5 parts per 100 parts of resin compared to when epoxidized soybean oil was used,
Low temperature circular deflection is reduced to about 5-7°C.

However, the use of the epoxidized octyl tarate has the effect of reducing the hardness, tensile strength, and tear strength of the film, for example. Incorporation of the epoxy stabilizer increases both the photostability and thermal stability of the resin. Samples 8 to 11 show the effect of adding calories to chlorinated polyethylene.

This can be compared to the sample 5 control. In general, chlorinated polyethylene 15 weight? When the following is added, the elongation rate is improved, although other desired features are slightly lowered. Sample 12,1
3 shows products 1 obtained by caroeing the internal plasticized resin of the present invention at different temperatures.

The enclosures are virtually identical, thus indicating that they can be processed at lower temperatures. Example 3 This example illustrates the mill thermal stability of various internally plasticized resins of the present invention.

Compressible film compositions for the following samples were prepared using the following ingredients:

Table 7 shows the processing degree of the diroll mill, the type of stabilizer, and a description of the appearance of the film.

Appearance Sample 1: Even after 160 minutes of treatment, no increase in color was observed compared to the initial pool color after 10 minutes.

Sample 2: Even after 160 minutes of treatment, no increase in coloration was observed compared to the initial pool color after 10 minutes.

Sample 3: After about 90 minutes, the film surface became rough and pale in color.

Sample 4: After about 80 minutes, the film surface became rough and some yellow was observed.

Sample 5: After about 90 minutes, the film surface became rough and some yellow was observed.

Notes: 1 Mill operations were carried out using a Nirollo mill at the temperatures shown in Table 2.

The temperature before / indicates the front roll temperature, and the temperature after / indicates the back roll temperature.

2. Ba-Cd and Ba-Cd-Zn refer to Ba-Cd and Ba-Cd-Zn thermal stabilizers.

The epoxidized stabilizer includes epoxidized soybean oil and epoxidized octyl tarate. Phosphite chelating agent is
6 Mark C゛. Phr indicates the amount of resin per 100 parts by weight. Example 4 This example shows the results of a method of measuring smoke in a smoke density chamber developed by the Fire Research Group of the National Bureau of Standards.

(D. GrOss, J. J. LOflusandA-F
-ROberlsOn,ASTM・Specl'T
electricalPubllcatiOn422, l66
-204 Sada 1969) The smoke density chamber contains 7.62×7
2.5W/CTli with 62CrI1 surface (7)
It is equipped with a radiant heat heater, a Provan-air pilot burner, a vertical light beam, a photomultiply tube detector, and a microphotometer to prevent light attenuation due to the increase in smoke in the room. It was designed to be recorded.

During the smoke generation test, the chamber is sealed to prevent combustion materials and smoke from leaking.The test was conducted in both smoke mode (Table 8) and flame mode (Table 9). (1)
The value is the result of two tests. End of 7L. 0
．． I. (Limiting Oxygen Oxygen required to continue combustion when lit.

Does a high value mean high flame retardancy? Analysis of the data shown in the table shows that under smoke generation conditions, the internal plasticized resin film of the present invention without flame retardant additives produces 65 to 68% more smoke than a similar external plasticized film. This shows that there are few

This is true whether it is per unit of weight of the original sample or per unit of burned weight. Additionally, in tests under smoke conditions, the flame retardant added films showed even better smoke reduction, i.e., a 78% smoke reduction compared to the flame retardant added externally plasticized resin films. ing. Even in the case of combustion mode, the internal plasticized film of the present invention
815P] Compared to plasticized film, smoke emission is reduced by approximately 30% when no flame retardant is added, and approximately 50% when flame retardant is added. It was done. Example 5 This example shows an example of producing an internal plasticized copolymer having a higher content of vinyl chloride component than the copolymer produced in Example 1. This indicates a mixture of plasticized polymers.

The following ingredients were used.

These are expressed in parts by weight. Vinyl chloride, acrylate and vinyl phosphonate monomers were copolymerized in the following manner. 1. The suspending agent was dissolved in a portion of pure water and charged into a reaction apparatus together with the remaining pure water.

The mixture is briefly mixed with peroxycarbonate and heptane. The longitudinal direction is at the tip of the sample as the lowest mole percent of oxygen content in the cord mixture.

Initiator mixture was added.

2. The acrylate and vinylphosphonate monomers were added.

3. The reactor was sealed and vacuum was applied for 10 minutes (approx.
The air was evacuated from the reactor (to create a vacuum of 2-635 mm Hg), vinyl chloride monomer gas was introduced to restore the vacuum, and this operation was repeated to introduce vinyl chloride monomer into the reactor.

4. The stirrer was rotated at 351 rpm and the reactor heated to 50° C. until the pressure decreased to 4.2k9/CTli from the maximum pressure indicating the start of the reaction.

Evacuate the 5.44 liter reactor to 70.7 CT1
The product was freed of residual monomer over a period of 1 hour by introducing nitrogen at a rate of t/sec.

6. The reactor was cooled and the polymer particles were removed by centrifugation.

The particles were dried in a fluidized bed with air at 30°C. 7.
The dried copolymer was milled using a Fitz mill and sieved through a 30 mesh sieve.

C:2-EllA:BB is 76:17.3:6.7 weight? The copolymer prepared by introducing components in the proportion of VC
:2-EHA, :BB is 73.6:18.2:8.2 weight? It is a copolymer consisting of the following components, and its specific viscosity is 2 when measured at 25°C as a 1% by weight solution of cyclohexanone.
,72.

This copolymer and the copolymer of samples 12 and 13 of Example 2 (C:2-EHA:BB-57.4:31.5:11.
A film was produced using a composition containing the following components in the following amounts.

The composition was mixed, processed in a diroll mill heated to 154°C and 157°C, fluxed for about 7 minutes, and then compression molded at 160°C to a thickness of 0.09 to 0.12°C.
A CT11 film was produced.

The results of testing the physical health of these samples are shown in the table below.
The data in this table shows that by blending the hard and soft copolymers of the present invention in desired proportions, the material and hardness of the flexible film can be changed as desired. This shows that it is possible to Example 6 This example shows the results when using a gamma acrylate comonomer that does not have the function of an internally plasticized resin and has an alkyl group with a carbon number less than a specific number. It shows.

The terpolymers shown in the table below were prepared by suspension polymerization of the ingredients shown in the table for 13 hours at about 46°C.

The components are given in parts by weight, using a 10% heptane solution of isopropyl peroxycarbonate as the initiator and hydropropyl methyl cellulose (1 wt. solution) as the suspending agent. Using the following ingredients, including each of the terpolymers listed in the table above, the various test nefilm compositions shown in the table were prepared using the compressible film compositions according to the method of Example 2. .
I did this.

The data shown in the above table shows that when a class of terpolymers is prepared using lower alkyl (C2 or C4 alkyl) acrylates together with vinyl chloride and bis(hydroxycarbyl)vinylphosphonate, higher alkyl acrylates are produced as in the present invention. le (
This explains why the internally plasticized resin obtained when C8 aluminum acrylate was used could not be removed.

Claims (1)

[Scope of Claims] 1 a) 50 to 85% by weight of structural units represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ b) Represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ 3 to 47% by weight of a structural unit in which R'' is a C_6 to C_1_0 alkyl group, and c) a structural unit represented by the general formula ▲There are numerical formulas, chemical formulas, tables, etc.▼, and in the formula, X is selected from the group consisting of hydrogen, halogen, cyano group, aryl group, C_1 to C_1_8 alkyl group, and ▲numerical formula, chemical formula, table, etc.▼, and in the formula, R and R' are hydrogen and carbon It is an aliphatic or aromatic hydrocarbyl group or substituted hydrocarbyl group having up to 18 atoms, and R and R' may be the same or different, or a single group in which both are bonded. ,
An internally plasticized copolymer comprising 3 to 47% by weight of structural units. 2. The copolymer according to claim 1, which contains 55 to 80% by weight of structural units represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼. 3. The compound according to claim 1, which is represented by the general formula ▲There are numerical formulas, chemical formulas, tables, etc.▼, and contains 10 to 35% by weight of structural units in which R″ is a C_6 to C_1_0 alkyl group. Copolymer. 4 A patent containing 5 to 25% by weight of structural units represented by the general formula ▲Mathematical formula, chemical formula, table, etc.▼, where R and R' are C_1 to C_8 alkyl or haloalkyl groups. A copolymer according to Claim 1. 5. The structural unit represented by the general formula ▲There are numerical formulas, chemical formulas, tables, etc.▼ In the formula, R'' is a 2-ethylhexyl group, Claim 1 Copolymer described in section. 6. The structural unit represented by the general formula ▲ includes numerical formulas, chemical formulas, tables, etc. Copolymer. 7 a) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ 56 to 58% by weight of structural units, and b) General formula ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ Represented by R 29 to 31% by weight of structural units in which `` is a C_6 to C_1_0 alkyl group; 11 to 13% by weight of a certain structural unit 8 In the structural unit represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼, R″ is a 2-ethylhexyl group, the copolymer according to claim 7 . 9 a) 56-58% by weight of structural units represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ b) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R 29 to 31% by weight of structural units in which `` is a 2-ethylhexyl group; , or 11 to 13% by weight of structural units that are 2-ethylhexyl groups or mixtures thereof,
A copolymer according to claim 8. 10 a) 73 to 75% by weight of structural units represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ and b) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R 17 to 19% by weight of structural units in which `` is a C_6 to C_1_0 alkyl group; A copolymer according to claim 1, comprising 7 to 9% by weight of a certain structural unit. 11. The structural unit represented by the general formula ▲There are numerical formulas, chemical formulas, tables, etc. is C_8~C_1
The copolymer according to claim 1, 7 or 10, which is a _0 alkyl group.