JPH0625320B2 - Hydroxyl group-containing modified chlorinated polyolefin composition and process for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a coating composition containing a hydroxyl group-containing modified chlorinated polyolefin and a method for producing the same.

More particularly, it relates to a novel resin that gives a long-term stable and tough coating film, and a coating composition using the same.

[Conventional technology]

Chlorinated products of polyethylene, polypropylene, ethylene-propylene copolymer, etc. are called chlorinated rubber resins and are widely used as anticorrosion paints and architectural undercoats. The reason is that the chlorinated rubber paint is
This is because it has excellent quick-drying properties and chemical resistance. However, in terms of long-term weather resistance and anticorrosion, it is inferior to that of epoxy or urethane paints.

[Problems to be solved by the invention] Therefore, as a resin capable of maintaining the characteristics of these chlorinated rubber-based resins and forming a stable and tough coating film for a long period of time, a resin obtained by introducing a hydroxyl group into the above chlorinated polyolefin is used as a base. The present invention has been accomplished based on the following idea of paint design by variously studying the production of the resin for reactive paint and the method for making the paint.

1. A polyolefin modified with a carboxylic acid anhydride having an unsaturated double bond such as maleic anhydride is synthesized from a polyolefin, but a low molecular weight one is used in consideration of workability of the paint. However, at least one unsaturated carboxylic acid anhydride group should be contained in one molecule.

2. The above modified polyolefin is dissolved in a chlorine resistant solvent and chlorinated in the presence of a catalyst to synthesize a chlorinated product of the modified polyolefin.

3. By reacting a chlorinated product of a modified polyolefin with a polyhydric alcohol having two or more hydroxyl groups, a part of the hydroxyl groups is used for esterification, and the remaining hydroxyl groups are left in the polymer, whereby a hydroxyl group-containing chlorinated polyolefin ( Hereinafter, simply referred to as CPO-OH) is synthesized.

4. A paint is prepared by dissolving CPO-OH in an organic solvent and kneading the pigment.

5. A predetermined amount (at least corresponding to the calculated hydroxyl group equivalent) of isocyanate or polyisocyanate is added to the above coating composition and mixed well.

6. This paint is applied with a brush, spray, etc., and naturally dried and crosslinked or polymerized at room temperature. As a result, a chlorinated rubber-based quick-drying coating having improved toughness, heat resistance, and solvent resistance of the coating film and good recoating can be easily obtained.

Various methods for improving the drawbacks of the chlorinated rubber resin have already been proposed. For example, JP-A-62-95372 proposes a method of curing an chlorinated polyolefin having a hydroxyl group introduced therein with an isocyanate as an adhesive resin composition in a mixed system of a chlorinated polyolefin, a hydroxyl group-containing acrylic ester and a liquid rubber. However, since it is difficult to effectively graft acrylic acid having a hydroxyl group onto a chlorinated polyolefin by the method, it is possible to
An attempt is made to improve the grafting efficiency by using a liquid rubber having C = C-in combination. Further, JP-A-58-84811 describes a method of reacting a polyol ester of maleic anhydride obtained by reacting maleic anhydride with a polyol with a polyolefin. It is a method for producing a modified polyolefin for the purpose of maintenance of an apparatus, which is different from the present invention both in the method and in the field of use, and is also completely different from the embodiment of the present invention in which the polyolefin is dissolved in an organic solvent.

[Means for Solving the Problems]

The gist of the present invention is to add a carboxylic acid anhydride having an unsaturated double bond to a polyolefin, and then chlorinate the carboxylic acid anhydride to obtain a modified chlorinated polyolefin, which is reacted with a polyhydric alcohol. The present invention relates to a coating composition using a group-containing modified chlorinated polyolefin and a method for producing the same.

Further, the present inventor has previously proposed in JP-A-63-131430 a method of chlorinating and reducing an oxidized polyolefin obtained by thermally decomposing a polyolefin with oxygen to contain a hydroxyl group. It is different from the one obtained by subjecting the carboxylic acid anhydride adduct to an esterification reaction with a polyhydric alcohol.

The polyolefin used in the present invention is a polyolefin such as polyethylene, polypropylene, ethylene / propylene copolymer, ethylene vinyl acetate, etc. The polymer having a polymerization degree of about 1000 to 50,000 is used because it is used as a coating material such as paint or ink. preferable. If it is higher than this, the viscosity of the obtained resin is high and it is inconvenient for coating or handling. If it is lower than this, the coated surface is too soft, and it is undesirably soiled or damaged.

The acid anhydride having an unsaturated double bond used in the present invention is preferably an acid anhydride such as maleic anhydride, itaconic anhydride and citraconic anhydride. The reason is that when reacting with a polyhydric alcohol, a ring-opening reaction first occurs and a single molecule reaction selectively occurs. However, even if the ring-opening reaction occurs, an esterification reaction occurs, so the above unsaturated acid may also be used. .

Next, the chlorination method in the chlorination step is carried out by using a commonly used chlorine-resistant solvent such as carbon tetrachloride, trichloroethylene, tetrachloroethane or the like under pressure or under normal pressure to dissolve benzoyl peroxide, It is chlorinated by gaseous chlorine using peroxides such as dicumyl peroxide, lauroyl peroxide, tert-butyl oxide and ultraviolet rays as a catalyst. The content of chlorine is not particularly limited, but is preferably 40 to 60% in consideration of suitability for coating. This is determined by the solubility in an organic solvent and the flexibility of the coating film.

The polyhydric alcohol used in the present invention includes ethylene glycol, propylene glycol, 1.4-butanediol,
It contains 1.5-pentanediol, 1.6-hexanediol, cyclopentane-1.2 diol, cyclohexane-1.2-diol, glycerin, propanediol, bisphenol A, trimethylolpropane, pentaerythritol, etc., but the reaction is rapid and efficient. High boiling alcohols capable of high temperature reaction are preferred for the purpose.

Further, the organic solvent used for varnishing is a solvent generally used for paints, varnishes, inks, etc., for example, xylene, toluene, dimethylbenzene etc. as an aromatic solvent, ethyl acetate, butyl acetate etc. as an ester solvent, a ketone solvent. As such, methyl ethyl ketone, methyl isobutyl ketone, etc. are used.

Isocyanates used in the present invention include tolylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 4,
4'-Diphenylmethane diisocyanate and derivatives thereof such as Coronate HL (Japan Polyurethane Industry Co., Ltd.) and Desmodur L (Bayer Co.) are used.

The CPO-OH resin of the present invention reacts with an isocyanate compound to form an excellent cured coating film.
The durability of the undercoating agent and the like can be improved. This is a performance that cannot be expected from conventional chlorinated rubber paints and the like.

〔Example〕

 The present invention will be specifically described below with reference to examples.

Production Example-I 1000 g of low molecular weight polyethylene having an average molecular weight of 4500 was placed in a 2 separable flask and melted in an oil bath at 200 ° C. Add 40 g of maleic anhydride and stir well, and add benzoyl peroxide 4 to 100 ml of carbon tetrachloride.
The solution in which g is dissolved is added in 30 minutes. 2 after addition
The Hrs reaction was performed, and the volatile matter was removed under a vacuum of 600 mm or more of mercury column to remove the unreacted monomer and the volatile matter.

The maleic anhydride-modified polyethylene obtained above is thoroughly ground in a mortar and washed in acetone. It is dried and ground. After performing this three times, IR absorption spectrum was taken, and it was confirmed from the existence of the maximum absorption wavelength near 1800 cm ^{−1 that} maleic anhydride was added to polyethylene.

Then, 1000 g of maleic anhydride-modified polyethylene was completely dissolved in 10 carbon tetrachloride at a temperature of 2 atm 100 ° C., and while irradiating with ultraviolet rays, gaseous chlorine was blown from the bottom for chlorination. The reaction solutions were sequentially withdrawn according to the amount of chlorine blown in, and chlorinated products of maleic anhydride-modified polyethylene having different chlorination degrees were collected.

Three points of 40, 50 and 60% calculated from the amount of blown chlorine were sampled. Subsequently, carbon tetrachloride was removed as much as possible from these reaction liquids by distillation to obtain a high-temperature high-viscosity solution, which was extruded and solidified by a vented extruder at 100 ° C.

Each of the chlorinated products obtained above is dissolved in toluene to prepare a 10% solution, which is dropped into a large amount of ethanol to precipitate a resin, which is then dried. Film formation or KBr tablets are prepared according to the form of each, and the IR spectrum is taken. 3000-2800 due to chlorination
absorption of cm ^-1 (C-H) is broad (C-C) absorption was confirmed to have increased to decrease 726~685cm ^-1.

The above-mentioned maleic anhydride-modified chlorinated polyethylene with chlorine content of 40, 50, 60% is crushed to about 30 mesh and 300
Add 18 g of 1,4-butanediol to g and mix well.

This was placed in a one-separable flask equipped with a stirrer, melted, and reacted at 200 ° C. for 30 minutes. At this time, if the temperature is sufficiently high, the ring-opening reaction easily occurs without using a catalyst.

The obtained hydroxylated product of maleic anhydride-modified chlorinated polyethylene (hereinafter referred to as CPE-OH),
After dissolving in toluene to make a 10% solution, the solution is dropped into a large amount of ethanol to precipitate the resin and overdry. This 3
After repeating the operation repeatedly and drying completely under reduced pressure, an IR spectrum was taken, and broad absorption was observed at 3600 to 3200 cm ^−1, and it was confirmed that an —OH group was introduced.

When the CPE-OH thus obtained was made into a 40% xylene solution and the solubility was confirmed, it was found that a uniform solution was obtained. Moreover, when the viscosity at 25 ° C was measured, it was found that CPE-OH with a chlorination degree of 40% was 480 cps and CPE-OH with a chlorination degree of 50%.
Was 410 cps and 60% CPE-OH was 380 cps.

This xylene solution was used as CPE-OH-1 and CPE, respectively.
They are called -OH-2 and CPE-OH-3 and used for the subsequent tests.

Production Example-II Isotactic polypropylene with an average molecular weight of 25,000
1000 g was put into a 2 separable flask and melted at 200 ° C. with stirring. To this, 30 g of maleic anhydride was added and mixed well, and then 3 g of dicumyl peroxide diluted with 100 ml of carbon tetrachloride was added over 30 minutes. After the addition was completed, the reaction was carried out for 2 hours. For the reaction product, the carboxyl group was confirmed by infrared absorption spectrum in the same manner as in Production Example I. Next, maleic anhydride modified polypropylene 1000g
Was dissolved in 10 carbon tetrachloride at a temperature of 2 atm 100 ° C., and chlorination was performed while irradiating with ultraviolet rays. Amount of chlorine blown
Chlorides of 45% and 55% were obtained. Remove carbon tetrachloride in the reaction solution by concentrating it as much as possible, and remove it with an extruder with a head at 110 ° C.
To obtain an extruded solid.

It was confirmed that this product was chlorinated in the same manner as in Production Example-I.

Next, chlorinated products of maleic anhydride-modified polypropylene with a chlorination degree of 45% and 55%, with 500g each, with a stirrer 1
It was put in a separable flask and melted at 180 ° C., 25 g of 1.6-hexanediol was added to each, and the mixture was stirred well and reacted for 30 minutes. It was confirmed that a hydroxyl group was introduced by the same method as in Production Example-I.

The hydroxylated product of maleic anhydride-modified chlorinated polypropylene (hereinafter referred to as CPP-OH) thus obtained was dissolved in xylene to a concentration of 30%, and the viscosity at 25 ° C. was measured with a viscometer. Chlorine 45% 450 cps, 5
5% was a uniform solution at 360 cps. CP for the former
P-OH-1 and the latter are called CPP-OH-2 and are used for the subsequent tests.

Example-I CPE-OH-1, CPE-OH- obtained in Preparation Example-I
2. Using CPE-OH-3, an overcoat paint was prepared by the SG mill with the following formulation.

1. Paint composition The above compound was put in an SG mill, 100 g of glass beads was added, and the mixture was kneaded for 1 hr to prepare a coating material.

2. Test panel preparation method For 100 g of the prepared paint, a curing agent (Coronate-
HL, Nippon Polyurethane Industry) 6.2g, SG
Stir well on the mill for 10 minutes. No curing agent was added to the chlorinated rubber paint of the comparative composition.

The above paint was applied twice to a sandplast plate which had been previously coated with an inorganic zinc primer and dried, and air dried for 7 days, and then the following coating test was conducted.

3. Test method Test method (1) Adhesion of the coating film Cross-cut test, indent the 2 mm gaps on the coating film, attach cellophane tape on it, and peel strongly.

(2) Impact test Mandrel impact tester Load 500g, height 30cm, 50cm Evaluation ◎ No peeling or cracking ○ No peeling, cracking × Peeling or cracking (3) Drawing test After drawing under 500g load, draw with cellophane tape Peel off.

◎ No peeling ○ Slight peeling × Peeling (4) Weather resistance test 0,300,600,100 by Sun Shine weather meter
Appearance and gloss measurement after 0Hrs (5) Secondary physical properties (weather resistance test 1000Hrs After 1000Hrs, carry out according to test (1), (2), (3).

(6) Solvent resistance test Observing toluene solvent resistance of the test panel after left at room temperature for 1 month Evaluation ○ Insoluble in toluene × Soluble in toluene 4. Test results Types of paint resins and paint No. Example CPE-OH-1 …… 40% chlorination, 1.4-butanediol treatment Example CPE-OH-2 …… 50% chlorination, 1.4-butanediol Treatment Example CPE-OH-3 …… 60% chlorination, 1.4-butanediol treatment Comparative Example …… Chlorinated rubber (CR-10) Example-II CPP-OH-1, CPP-OH-2 obtained in Production Example-II
Was used to prepare a topcoat paint with the following formulation using an SG mill.

1. Paint composition The above formulation was put in an SG mill, 100 g of glass beads were added, and the mixture was kneaded for 1 hr to prepare a coating material.

2. The test panel preparation method is the same as above. The test method is the same as above 4. Test results Types of paint resins and paint No. Example CPP-OH-1 …… 45% chlorination, 1.6-hexanediol treatment Example CPP-OH-2 …… 55% chlorination, 1.6-hexanediol Treatment Comparative example: Chlorinated polypropylene (Super Clone 106
H) [Effect of the invention] From the above results, the conventional chlorinated rubber-based paint (comparative example) is poor in long-term durability because it cannot be a paint without a plasticizer. It is clear that not only the physical properties are very good, but also the solvent resistance is improved.

Claims (3)

[Claims] 1. A hydroxyl group-containing modified chlorinated polyolefin obtained by adding a carboxylic acid anhydride having an unsaturated double bond to a polyolefin, chlorinating the carboxylic acid anhydride, and then reacting it with a polyhydric alcohol. Coating composition. 2. The coating composition according to claim 1, wherein the hydroxyl group-containing modified chlorinated polyolefin is added with an isocyanate and / or polyisocyanate in an equimolar amount or more based on the hydroxyl group equivalent of the polyolefin. 3. A hydroxyl group-containing modified chlorination product obtained by adding a carboxylic acid anhydride having an unsaturated double bond to a polyolefin, and then chlorinating the resulting product into a modified chlorinated polyolefin and reacting the resulting product with a polyhydric alcohol. A method for producing a coating composition comprising a polyolefin.