JP7767889B2 - Hydroxyl-containing chlorosulfonated polyolefin - Google Patents

Description

The present invention relates to hydroxyl group-containing chlorosulfonated polyolefins.

Chlorosulfonated polyolefins have excellent mechanical properties, heat resistance, abrasion resistance, chemical resistance, and bright color, and are therefore used in a variety of applications, including hose covers, electrical wire coatings, packing, gaskets, rolls, and escalator handrails. Chlorosulfonated polyolefins can also be dissolved or dispersed in solvents or water and used as adhesives, coatings, paints, etc.

However, crosslinking of chlorosulfonated polyolefins typically requires high temperatures of over 140°C, so when used as a coating or paint, the substrate must be heat resistant to at least 140°C, limiting its use.

Patent Document 1 describes how chlorosulfonated polyethylene paint exhibits abrasion resistance and weather resistance when dried at 100°C for 15 minutes, but makes no mention of tensile properties.

Patent Document 2 proposes using organic peroxides with a one-hour half-life temperature of 120°C or less as crosslinking agents for ethylene-propylene rubber, ethylene-propylene-diene rubber, acrylonitrile-butadiene rubber, and hydrogenated acrylonitrile-butadiene rubber. While adjusting the half-life temperature of the organic peroxide makes it possible to crosslink at low temperatures, there are limitations to their use because organic peroxides cannot crosslink in air.

Chlorosulfonated polyolefins have excellent mechanical properties, heat resistance, abrasion resistance, chemical resistance, and bright color, but their applications are limited because crosslinking requires high temperatures of over 140°C. Therefore, there was a demand for chlorosulfonated polyolefins that could be crosslinked at low temperatures.

Japanese Patent Application Publication No. 2-74339 Patent No. 5268313

The present invention was made in consideration of the above-mentioned problems, and provides a hydroxyl-containing chlorosulfonated polyolefin that can be crosslinked at low temperatures.

As a result of extensive research into solving the above-mentioned problems, the inventors have discovered that the hydroxyl-containing chlorosulfonated polyolefin of the present invention solves the above-mentioned problems. Specifically, the present invention encompasses the following aspects [1] to [11].

[1] A hydroxyl group-containing chlorosulfonated polyolefin having chlorine, chlorosulfone groups, and hydroxyl groups in the polyolefin backbone.

[2] The hydroxyl group-containing chlorosulfonated polyolefin described in [1], wherein the chlorine content is 20 to 50% by weight.

[3] The hydroxyl group-containing chlorosulfonated polyolefin according to [1] or [2], wherein the content of sulfur derived from chlorosulfone groups is 0.1 to 3% by weight.

[4] The hydroxyl group-containing chlorosulfonated polyolefin according to any one of [1] to [3], wherein the hydroxyl group content is 3 to 100 mmol/100 g.

[5] The hydroxyl group-containing chlorosulfonated polyolefin according to any one of [1] to [4], having a number average molecular weight of 10,000 to 150,000.

[6] The hydroxyl group-containing chlorosulfonated polyolefin described in any one of [1] to [5], further containing an acetoxy group in the polyolefin backbone.

[7] The hydroxyl group-containing chlorosulfonated polyolefin according to [6], wherein the acetoxy group content is 300 mmol/100 g or less.

[8] A urethane-forming composition containing the hydroxyl group-containing chlorosulfonated chlorinated polyolefin described in any one of [1] to [7] and a polyisocyanate.

[9] A polyurethane that is a cured product of the urethane-forming composition described in [8].

[10] A paint containing the polyurethane described in [9].

[11] A coating containing the polyurethane described in [9].

The hydroxyl group-containing chlorosulfonated polyolefin, which is one aspect of the present invention, can be crosslinked at lower temperatures than conventionally known chlorosulfonated polyolefins, making it possible to coat materials with low heat resistance, which was previously difficult to do, and obtain a crosslinked coating.

The present invention is described in detail below.

One embodiment of the present invention is a hydroxyl-containing chlorosulfonated polyolefin having chlorine, chlorosulfonic groups, and hydroxyl groups in the polyolefin backbone. To achieve excellent flexibility and strength, the chlorine content is preferably 20 to 50 wt%, more preferably 25 to 45 wt%. The sulfur content derived from chlorosulfonic groups is preferably 0.1 to 3 wt%, more preferably 0.5 to 2 wt%. To achieve excellent metal adhesion, it is preferably 0.1 wt% or more, more preferably 0.5 wt% or more. From the perspective of processability, the sulfur content is preferably 3 wt% or less, more preferably 2 wt% or less. To achieve both excellent flexibility and mechanical properties, the hydroxyl group content is preferably 3 to 100 mmol/100 g, more preferably 5 to 70 mmol/100 g. To achieve both excellent mechanical properties and processability, the number average molecular weight is preferably 10,000 to 150,000, more preferably 30,000 to 100,000. The number average molecular weight refers to the value (polystyrene equivalent) measured by gel permeation chromatography (hereinafter abbreviated as GPC).

The polyolefin skeleton of the hydroxyl group-containing chlorosulfonated polyolefin may contain acetoxy groups. To achieve good color stability, the acetoxy group content is preferably 300 mmol/100 g or less, and more preferably 200 mmol/100 g or less.

The method for synthesizing hydroxyl group-containing chlorosulfonated polyolefins is not particularly limited, but examples include a method in which chlorosulfonated ethylene-vinyl acetate copolymer is deesterified by transesterification with an alcohol under acidic or basic conditions, or a method in which saponified ethylene-vinyl acetate copolymer is chlorosulfonated. Among these, the method of utilizing transesterification of chlorosulfonated ethylene-vinyl acetate copolymer with an alcohol under acidic conditions is preferred because it requires a shorter reaction time.

Methods for obtaining the chlorosulfonated ethylene-vinyl acetate copolymer include, for example, a solution method in which the ethylene-vinyl acetate copolymer is dissolved in a solvent inert to the halogenation reaction and carried out in a homogeneous system, and a suspension method in which the ethylene-vinyl acetate copolymer is suspended in a solvent and reacted. Of these, the solution method is preferred when considering the flexibility of the rubber.

The method for synthesizing chlorosulfonated ethylene-vinyl acetate copolymer using a solution method is shown below.

After dissolving ethylene-vinyl acetate copolymer in a solvent, a radical generator and a chlorosulfonating agent are added. The reaction temperature is not particularly limited, but is typically between 60 and 180°C. The reaction pressure is also not particularly limited, but is typically between atmospheric pressure and 1.0 MPa. Examples of solvents for dissolving ethylene-vinyl acetate copolymer include chloroform, carbon tetrachloride, 1,1,2-trichloroethane, and chlorobenzene. Examples of radical generators include α,α'-azobisisobutyronitrile, azobiscyclohexanecarbonitrile, and 2,2'-azobis(2,4-dimethylvaleronitrile). Examples of organic peroxides include benzoyl peroxide, acetyl peroxide, t-butyl peroxide, and t-butyl perbenzoate. Azo compounds are preferred due to their high handling stability, and α,α'-azobisisobutyronitrile is particularly preferred due to the moderate chlorination and chlorosulfonation reactions that occur. Examples of chlorosulfonating agents include chlorine gas and sulfurous acid gas, chlorine gas and sulfuryl chloride, sulfurous acid gas and sulfuryl chloride, sulfuryl chloride alone, and chlorine gas, sulfurous acid gas and sulfuryl chloride. When sulfuryl chloride is used as the chlorosulfonating agent, an amine compound such as pyridine, quinoline, dimethylaniline, or piperidine may be used as a co-catalyst, if necessary. After the reaction is complete, the hydrogen chloride and sulfurous acid gas dissolved in the solution are removed from the reaction system by blowing in an inert gas such as nitrogen under solvent reflux. The resulting chlorosulfonated ethylene-vinyl acetate copolymer can be separated into polymer and solvent by steam distillation, drum drying, extrusion drying, or other methods, as needed.

The following describes a method for synthesizing hydroxyl-containing chlorosulfonated polyolefins using the transesterification reaction of chlorosulfonated ethylene-vinyl acetate copolymer with alcohol under acidic conditions. After dissolving the chlorosulfonated ethylene-vinyl acetate copolymer in a solvent, an acid and an alcohol are added. The reaction temperature is not particularly limited, but is generally between 10 and 100°C. Examples of solvents for dissolving the chlorosulfonated ethylene-vinyl acetate copolymer include halogenated organic solvents such as chloroform, methylene chloride, and 1,1,2-trichloroethane, and aromatic organic solvents such as benzene, toluene, and xylene. The acid used in the reaction can be any acid that dissolves in a mixture of the solvent and alcohol, including hydrogen chloride, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Hydrogen chloride is preferred for its ease of removal after the reaction. Examples of alcohols include methanol, ethanol, n-propanol, isopropanol, and n-butanol. Primary alcohols are preferred due to their fast reaction rate. Alcohols with four or fewer carbon atoms are also preferred for their ease of removal. Methanol is particularly preferred because it has a fast reaction rate and is easy to remove. Methods for separating the polymer from the reaction solution after the reaction is complete include, for example, distilling off the solvent under reduced pressure, distilling off the solvent using a drum dryer, and reprecipitation, in which the reaction solution is poured into a poor solvent such as methanol to isolate the polymer.

The method for crosslinking hydroxyl-containing chlorosulfonated polyolefin is not particularly limited, but examples include a method in which a crosslinking agent is added to a solution of hydroxyl-containing chlorosulfonated polyolefin dissolved in an organic solvent, etc., and the solution is applied to a substrate, etc., the solvent is dried, and then the solution is aged to crosslink the polymer. To broaden the range of substrate applications, the drying and aging temperatures are preferably 120°C or lower, and more preferably 80°C or lower. For ease of operation, drying and aging are preferably performed in a gear oven or the like.

There are no particular limitations on the organic solvent used to dissolve the hydroxyl-containing chlorosulfonated polyolefin, but it is preferable to use one that dissolves the hydroxyl-containing chlorosulfonated polyolefin uniformly and that volatilizes under dry conditions. Examples of such organic solvents include benzene, toluene, xylene, ethylbenzene, chlorobenzene, methyl acetate, ethyl acetate, normal propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, methoxybutyl acetate, amyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, normal propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, methyl butyrate, methyl butyrate, normal propyl butyrate, isopropyl butyrate, butyl butyrate, isobutyl butyrate, methyl isobutyrate, ethyl isobutyrate, normal propyl isobutyrate, isopropyl isobutyrate, butyl isobutyrate, isobutyl isobutyrate, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, dibutyl ketone, and diisobutyl ketone.

The crosslinking agent used to crosslink the hydroxyl group-containing chlorosulfonated polyolefin is not particularly limited, but examples include polyisocyanates with two or more isocyanate groups per molecule, epoxy compounds with two or more epoxy groups per molecule, and sulfur. Polyisocyanates are preferred as crosslinking agents due to their excellent low-temperature crosslinking properties and the mechanical properties of the crosslinked product. Examples of polyisocyanates include, but are not limited to, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolidine diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tetramethylxylene diisocyanate, and 1,6-hexamethylene diisocyanate. , 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, norbornane diisocyanate, lysine ester triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, trimethylhexamethylene diisocyanate, isocyanate-containing prepolymers obtained by reacting these with polyols, and mixtures of two or more of these. Further included are modified products of these isocyanates (modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups, or oxazolidone groups) and condensates (sometimes referred to as polynuclear compounds) of polymethylene polyphenylene polyisocyanate (polymeric MDI). Aliphatic isocyanates are preferred because they yield crosslinked products with excellent mechanical properties and minimal yellowing. Examples include 1,6-hexamethylene diisocyanate and modified products thereof (modified products containing urethane groups, carbodiimide groups, allophanate groups, urea groups, biuret groups, isocyanurate groups, amide groups, imide groups, uretonimine groups, uretdione groups, or oxazolidone groups). These polyisocyanates may be used alone or in combination.

When using polyisocyanate as the crosslinking agent, a catalyst that accelerates the crosslinking reaction may be added. Examples of catalysts that accelerate the crosslinking reaction include, but are not limited to, organometallic compounds such as dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin dilaurate, as well as organic amines such as triethylenediamine and triethylamine, and their salts.

When crosslinking the hydroxyl group-containing chlorosulfonated polyolefin, additives such as epoxy resins, coating improvers, leveling agents, antifoaming agents, stabilizers such as antioxidants and UV absorbers, plasticizers, surfactants, pigments (e.g., titanium oxide), fillers (e.g., talc, calcium carbonate, silica, carbon, petroleum resins, tar, asphalt), organic or inorganic fine particles, antifungal agents, and silane coupling agents may be blended as needed.

The hydroxyl group-containing chlorosulfonated polyolefin can be used as a urethane-forming composition containing the hydroxyl group-containing chlorosulfonated polyolefin and the polyisocyanate. The urethane-forming composition can also be cured to form polyurethane.

The uses of the hydroxyl-containing chlorosulfonated polyolefin, which is one embodiment of the present invention, are not particularly limited, but include, for example, paints and coatings, and can be paints and coatings containing the polyurethane.

The present invention will now be described in detail based on examples, but the present invention should not be construed as being limited to these examples.

The values used in these examples were obtained in accordance with the following measurement methods:

<Chlorine content and sulfur content>
The chlorine content and sulfur content of the hydroxyl-containing chlorosulfonated polyolefin and chlorosulfonated ethylene-vinyl acetate copolymer were measured by the combustion flask method. To measure the chlorine content, approximately 20 mg of the hydroxyl-containing chlorosulfonated polyolefin was combusted according to the oxygen flask combustion method, and 15 mL of a 1.7 wt% aqueous hydrazinium sulfate solution was allowed to stand as an absorption solution. After 40 minutes, the absorption solution was washed out with approximately 100 mL of pure water, and then the chloride ions were quantified by potentiometric titration with a 0.5 N aqueous silver nitrate solution to measure the chlorine content.

To measure the sulfur content of hydroxyl-containing chlorosulfonated polyolefin, approximately 10 mg of hydroxyl-containing chlorosulfonated polyolefin was combusted using the oxygen flask combustion method, and approximately 10 mL of 3 wt. % hydrogen peroxide solution was allowed to stand as an absorption solution. After 40 minutes, the absorption solution was washed out with approximately 40 mL of pure water, and then approximately 1 mL of acetic acid, approximately 100 mL of 2-propanol, and approximately 0.47 mL of Arsenazo III were added. The sulfate ions in this solution were quantified by photometric titration using a 0.01 N barium acetate solution, and the sulfur content was measured.

<Acetoxy group content>
The acetoxy group content of the hydroxyl group-containing chlorosulfonated polyolefin and the chlorosulfonated ethylene-vinyl acetate copolymer was measured by ¹ H- ^NMR .
Approximately 100 mg of hydroxyl group-containing chlorosulfonated polyolefin or chlorosulfonated ethylene-vinyl acetate copolymer (W _P ) was dissolved in approximately 1 mL of deuterated chloroform, and approximately 8.8 mg of benzene (W _B ) was added as an internal standard substance, followed by ¹ H-NMR analysis using a 400 Hz NMR. From the obtained ¹ H-NMR chart, the integral values (S _B , S _Ac ) of benzene (7.35 ppm) and C H -OAc (4.73 to 5.47 ppm) were calculated, and the acetoxy group content was calculated using formula (1).

Acetoxy group content (mmol/100 g)=W _B ×S _Ac ×10 ⁵ /(W _P ×S _B ×78.11/6) (1)
<Hydroxyl group content>
The hydroxyl group amount was calculated from the formula (2) using the acetoxy group content (Ac _RM ) of the hydroxyl group-containing chlorosulfonated polyolefin measured by ¹ H-NMR and the acetoxy group content (Ac _SM ) of the chlorosulfonated ethylene-vinyl acetate copolymer used as the raw material.

Hydroxyl group content (mmol/100 g)=(Ac _SM × 100/(100−42.04×Ac _SM /1000))−(Ac _SM × 100/(100−42.04×Ac _SM /1000))×Ac _RM /Ac _SM (2)
<Measurement of molecular weight>
The molecular weight of the hydroxyl-containing chlorosulfonated polyolefin was measured by GPC of a polymer solution obtained by dissolving 10 mg of the hydroxyl-containing chlorosulfonated polyolefin in 10 mL of THF. The weight average molecular weight (Mw) was determined in terms of polystyrene using standard polystyrene (manufactured by Tosoh Corporation). The measurement conditions are shown below.

・Model: (product name) HLC8220GPC
Solvent: THF
Column temperature: 40°C
・Measurement concentration: 10mg/10mL
・Injection volume: 200μL
Column: TSKgel G7000HXL (manufactured by Tosoh Corporation) → 2 TSKgel GMHXL (manufactured by Tosoh Corporation) <Tensile test>
The tensile strength (TB) and elongation at break (EB) were measured in accordance with JIS K 6251. The measurement conditions are shown below.

Test equipment: VG-1G (manufactured by Toyo Seiki Co., Ltd.)
Measurement conditions: 25°C x 50% RH
Head speed: 200 mm/min. Dumbbell: No. 4 <Chlorosulfonated ethylene-vinyl acetate copolymer 1 synthesis>
In a nitrogen atmosphere, in a 40 L glass-lined autoclave, 2.6 kg of an ethylene-vinyl acetate copolymer (manufactured by Tosoh Corporation, trade name: Ultrathene 520F) having a melt mass flow rate (JIS K 6924-1) of 2.0 g/10 min and a vinyl acetate content of 8 wt% was dissolved in 12 L of 1,1,2-trichloroethane (manufactured by Tosoh Corporation) at 110°C. A solution of 1.8 g of α,α'-azobisisobutyronitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) dissolved in 1 kg of 1,1,2-trichloroethane and 5.6 kg of sulfuryl chloride (manufactured by Sumitomo Seika Chemicals Co., Ltd.) were added dropwise to this polymer solution over 140 minutes at 110°C. The pressure inside the reactor during the reaction was maintained at 0.25 MPa. After completion of the dropwise addition, the reaction was continued for 30 minutes, and then nitrogen was blown in for 2 hours. The reaction solution was dried in a drum dryer heated to 155° C. to remove the solvent, and chlorosulfonated ethylene-vinyl acetate copolymer 1 was obtained.

The chlorine content of the resulting chlorosulfonated ethylene-vinyl acetate copolymer 1 was 35.1% by weight, the sulfur content was 0.9% by weight, and the acetoxy group content was 56 mmol/100 g.

<Synthesis of chlorosulfonated ethylene-vinyl acetate copolymer 2>
Chlorosulfonated ethylene-vinyl acetate copolymer 2 was obtained in the same manner as in the synthesis of chlorosulfonated ethylene-vinyl acetate copolymer 1, except that the condition in the synthesis of chlorosulfonated ethylene-vinyl acetate copolymer 1 was changed from "a solution of 1.8 g of α,α'-azobisisobutyronitrile dissolved in 1 kg of 1,1,2-trichloroethane and 5.6 kg of sulfuryl chloride were added dropwise over 140 minutes" to "a solution of 1.6 g of α,α'-azobisisobutyronitrile dissolved in 0.9 kg of 1,1,2-trichloroethane and 4.4 kg of sulfuryl chloride were added dropwise over 120 minutes."

The chlorine content of the resulting chlorosulfonated ethylene-vinyl acetate copolymer 2 was 30.2% by weight, the sulfur content was 1.0% by weight, and the acetoxy group content was 60 mmol/100 g.

Example 1
140 g of chlorosulfonated ethylene-vinyl acetate copolymer 1 was dissolved in 1260 g of 1,1,2-trichloroethane, and the temperature was raised to 65°C. 123 g of a 6 wt% hydrogen chloride/methanol solution was added dropwise to this polymer solution over 2 hours. After the dropwise addition was completed, nitrogen was blown for 1 hour, the solvent was distilled off using an evaporator, and the resulting mixture was dried in a vacuum dryer to obtain hydroxyl group-containing chlorosulfonated polyolefin 1.

The resulting hydroxyl group-containing chlorosulfonated polyolefin 1 had a chlorine content of 35.5% by weight, a sulfur content of 0.9% by weight, an acetoxy group content of 31 mmol/100 g, and a hydroxyl group amount of 26 mmol/100 g.

100 parts by weight of the resulting hydroxyl-containing chlorosulfonated polyolefin 1 was dissolved in 247 parts by weight of toluene (Fujifilm Wako Pure Chemical Industries, Ltd.). 5.9 parts by weight of polyisocyanate (Coronate HXR, NCO content 21.9% by weight, Tosoh Corporation) and 0.01 parts by weight of catalyst were added to the toluene solution of hydroxyl-containing chlorosulfonated polyolefin 1, and the mixture was mixed and degassed using a planetary centrifugal mixer (Thinky Corporation, ARE-310) to obtain a composition for property evaluation. The resulting composition was applied to release paper to a dry film thickness of 100 μm. After allowing to stand at room temperature for 90 minutes, the mixture was heated in a dryer at 60°C for 30 minutes and then at 80°C for 30 minutes to remove the solvent, and then heat-treated at 50°C for 18 hours to obtain a crosslinked product. The tensile properties of this crosslinked product were measured. The results are shown in Table 1. As can be seen from Table 1, the crosslinked product had excellent tensile properties, with a TB of 24.0 MPa and an EB of 250%.

Example 2
Hydroxyl group-containing chlorosulfonated polyolefin 2 was obtained in the same manner as in Example 1, except that the condition in Example 1, "123 g of a 6 wt % hydrogen chloride/methanol solution was added dropwise over 2 hours," was changed to "69 g of a 6 wt % hydrogen chloride/methanol solution was added dropwise over 1 hour."

The resulting hydroxyl group-containing chlorosulfonated polyolefin 2 (B-2) had a chlorine content of 35.2% by weight, a sulfur content of 0.9% by weight, an acetoxy group content of 47 mmol/100 g, and a hydroxyl group amount of 8.6 mmol/100 g.

A crosslinked body was obtained in the same manner as in Example 1, except that 253 parts by weight of toluene and 8.3 parts by weight of polyisocyanate were used per 100 parts by weight of the obtained hydroxyl group-containing chlorosulfonated polyolefin 2 (B-2). The tensile properties of this crosslinked body were measured. The results are shown in Table 1. As can be seen from Table 1, the crosslinked body had excellent tensile properties, with a TB of 20.8 MPa and an EB of 310%.

Example 3
Hydroxyl group-containing chlorosulfonated polyolefin 3 (B-3) was obtained in the same manner as in Example 1, except that chlorosulfonated ethylene-vinyl acetate copolymer 2 was used instead of chlorosulfonated ethylene-vinyl acetate copolymer 1 in Example 1 and the conditions of "123 g of a 6 wt % hydrogen chloride/methanol solution was added dropwise over 2 hours" were changed to "65 g of a 6 wt % hydrogen chloride/methanol solution was added dropwise over 1 hour."

The resulting hydroxyl group-containing chlorosulfonated polyolefin 3 (B-3) had a chlorine content of 30.3% by weight, a sulfur content of 1.0% by weight, an acetoxy group content of 49 mmol/100 g, and a hydroxyl group content of 11 mmol/100 g.

A crosslinked body was obtained in the same manner as in Example 1, except that 259 parts by weight of toluene and 10.8 parts by weight of polyisocyanate were used per 100 parts by weight of the obtained hydroxyl group-containing chlorosulfonated polyolefin 3 (B-3). The tensile properties of this crosslinked body were measured. The results are shown in Table 1. As can be seen from Table 1, the crosslinked body had excellent tensile properties, with a TB of 9.1 MPa and an EB of 210%.

Comparative Example 1
A crosslinked product was obtained in the same manner as in Example 1, except that 257 parts by weight of toluene and 10 parts by weight of polyisocyanate were used relative to 100 parts by weight of chlorosulfonated ethylene-vinyl acetate copolymer 1 (A-1). The tensile properties of this crosslinked product were measured. The results are shown in Table 1. As can be seen from Table 1, the tensile properties showed that TB was 0.5 MPa and EB was 1900%, indicating insufficient crosslinking.

Comparative Example 2
A crosslinked product was obtained in the same manner as in Example 1, except that 250 parts by weight of toluene, 5 parts by weight of an acid acceptor for CSM (trade name: Kyowamag #150, manufactured by Kyowa Chemical Industry Co., Ltd.), and 2 parts by weight of a vulcanizing agent for CSM (trade name: Noccela TRA, manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) were used per 100 parts by weight of chlorosulfonated polyethylene (trade name: TOSO-CSM CN-1500, chlorine content 30% by weight, sulfur content 1.4% by weight, manufactured by Tosoh Corporation). The tensile properties of this crosslinked product were measured. The results are shown in Table 1. As can be seen from Table 1, the TB was 0.5 MPa and the EB was 1300%, indicating insufficient crosslinking.

The hydroxyl group-containing chlorosulfonated polyolefin of the present invention can be crosslinked at low temperatures, and thus can be used as a crosslinked product that has been crosslinked and molded in the same manner as conventional chlorosulfonated polyolefins, and can be used in a wide range of applications.

Claims (11)

A hydroxyl group-containing chlorosulfonated polyolefin having chlorine, chlorosulfone groups, and hydroxyl groups in the polyolefin skeleton. 2. The hydroxyl group-containing chlorosulfonated polyolefin according to claim 1, wherein the chlorine content is 20 to 50% by weight. 3. The hydroxyl group-containing chlorosulfonated polyolefin according to claim 1, wherein the content of sulfur derived from the chlorosulfone group is 0.1 to 3% by weight. 4. The hydroxyl group-containing chlorosulfonated polyolefin according to claim 1, wherein the content of the hydroxyl groups is 3 to 100 mmol/100 g. The hydroxyl group-containing chlorosulfonated polyolefin according to any one of claims 1 to 4, having a number average molecular weight of 10,000 to 150,000. The hydroxyl group-containing chlorosulfonated polyolefin according to any one of claims 1 to 5, wherein the polyolefin skeleton further contains an acetoxy group. 7. The hydroxyl group-containing chlorosulfonated polyolefin according to claim 6, wherein the content of the acetoxy group is 300 mmol/100 g or less. A urethane-forming composition comprising the hydroxyl group-containing chlorosulfonated polyolefin according to any one of claims 1 to 7 and a polyisocyanate. A polyurethane that is a cured product of the urethane-forming composition described in claim 8. A paint containing the polyurethane described in claim 9. A coating comprising the polyurethane of claim 9.