JPS63301266A - Protective varnish - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a new varnish that is resistant to strong acids and is also mechanically strong.

Conventional technology Thermosetting materials such as polyester, polystyrene,
Many materials, including thermoplastic materials such as (meth)acrylates, are susceptible to attack by strong acids such as sulfuric acid. This problem is particularly acute in the aircraft industry. For example, airlines on scheduled flights often have to pass through clouds containing about 75% sulfuric acid, which may be caused by volcanoes, in the atmosphere at an altitude of 10,000 m.

Problems to be Solved by the Invention The transparent parts of the fuselage surface are usually made of methyl polymethacrylate, which deteriorates quickly. For this reason, this transparent part needs to be polished frequently - or even replaced after every voyage.

In order to solve this problem, the applicant of the present patent has proposed that, after polymerization, it is not only not attacked by organic solvents, especially alcohols, sulfuric acid and other strong acids, but also completely adheres to thermosetting or thermoplastic materials. Finished with protective varnish. Another object of the invention is to provide a protective varnish which can be formed integrally with the material to be coated by heat and/or mechanical forces and which does not crack due to stresses on the surface.

According to the invention, a protective varnish comprising at least one halogenated solvent and/or at least one
The following polymers were added in the following proportions in a seed ketone solvent,
That is, - 95 to 99.9% by weight of a polymer (A) with an average molecular weight of 15.000 to goo, ooo, - 0.1 to 5% by weight of a polymer (B) with an average molecular weight of 500 to 4.000. The polymer (A) and the polymer (B) contain - at least one fluorinated monomer represented by the following chemical formula, H2C=C(R1)-C(O)-0- -C (R2) (R3)-C,F2. ,. l-m H
m... (I) (However, R1 is a methyl group, hydrogen atom, chlorine atom, or fluorine atom, and R2 and R3 are mHmCH3, CH2-CH, or CF, and may be the same or different from each other. , n is an integer of 1 to 20, and m is an integer of 0 to 2n) in an amount of 50 to 100% by weight; - at least one vinyl monomer (II).

Provided is a varnish characterized in that it is produced by polymerizing up to 50% by weight.

Surprisingly, the sample pieces coated with the varnish of the invention do not show any cracks even after bending tests in the presence of alcohol or acid.

For example, when measuring the crack threshold under the conditions described in the A I R9106A standard (see Example 1), for this sample piece the crack darkness value was approximately 1.9 Kg/mm2 in the presence of isopropanol. , the maximum cracking threshold in the presence of 75 wt% sulfuric acid is 2.8 Kg/mm2
It is.

The protective varnish of the present invention preferably contains 50 to 90% by weight of a halogen solvent and/or a ketone solvent.

Furthermore, the average molecular weight of the polymer (A) is from 50.000 to
300.000, and the average molecular weight of the polymer (B) is preferably 500 to 2.000.

Furthermore, the fluorinated monomer of chemical formula (I) has a 2°2.2
-trifluoroethyl acrylate or 2.2.2-
) Lifluoroethyl methacrylate is preferred.

Vinyl monomers (II) that can be used to produce polymers (A) and (B) include (meth)acrylic acid monomers such as methacrylic acid, ethyl acrylate,
(meth)acrylates such as butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, glycidyl methacrylate, or chlorinated (meth)acrylates such as 2-chloroethyl methacrylate (2-chloroethyl methacrylate), 2,2.2-) dichloroethyl methacrylate, etc. can be mentioned.

As halogenated solvents which can be used in the present invention, chlorinated solvents such as dichloromethane, chloroform, 1.degree. 2-dichloroethane, 1.1-dichloroethane, etc., or combinations of these solvents are particularly suitable. However, it is preferred to use dichloromethane alone or in combination with other chlorinated and/or ketone solvents. In this case, a varnish is obtained that completely adheres to the surface of the thermoset or thermoplastic material.

The ketone solvent in the present invention refers to a ketone group -C(O)
- means an organic substance containing at least one. Examples of ketone solvents that can be used in the present invention include acetone, methyl ethyl ketone, methyl isobutyl ketone, and isophorone. These ketone solvents may be used alone or in combination with other ketone solvents. Depending on the case, one or more halogen-based solvents and the above-mentioned ketone-based solvents may be used in combination.

The halogen solvent and/or ketone solvent should be 50 to 95% by weight of the varnish. This proportion is preferably 70-85% by weight.

In some cases, a polar solvent may be added to the varnish of the invention to dilute it.

Examples of the polar solvent used include ethyl acetate,
Examples include acetates such as butyl acetate. Also,
The varnishes of the present invention can also be diluted using solvents such as toluene, xylene, etc. up to 10% by weight of the varnish.

Furthermore, the present invention provides a method for producing the above varnish. According to this method, at a temperature of 20-70°C, preferably 40-60°C, 50-100% by weight of at least one fluorinated monomer of formula (I) as defined above is added to Monomers containing from 0 to 50 weight percent of at least one of the monomers (n) are polymerized in solution in the presence of at least one catalyst.

In a preferred embodiment of the present invention, the above polymerization reaction is carried out in a chlorinated solvent, which is a halogenated solvent, such as dichloromethane, 1,2-dichloroethane, 1,1-dichloroethane, etc., or a combination of these solvents. Also,
The above polymerization reaction can also be carried out in a solvent in which a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, or isophorone is combined with a halogen solvent.

Optionally, polar diluents and/or less polar diluents, or even mixtures of two or more of these diluents, are added to the solvent. Examples of the polar diluent include acetates such as ethyl acetate and butyl acetate. Furthermore, toluene and xylene are used as diluents with low polarity.

Suitable polymerization catalysts for the present invention include peroxides such as benzoyl peroxide, lauroyl peroxide, tertiobutyl perbenzoate, tertiobutyl perbenzoate, acetylcyclohexane sulfonyl peroxide, methyl ethyl ketone peroxide, tertiobutyl peroxide, peroxydicarbonates, For example, bis(4-cthiobutylcyclohexyl) peroxydicarbonate, n-butyl peroxydicarbonate, cyclohexyl peroxydicarbonate, bis(2
-ethylhexyl) peroxycarbonate and isopropyl peroxycarbonate. Also, azo compounds such as 2゜2゛-azobisisobutyronide I
It is also possible to use 4,4'-azobis(4-cyanopencune) acid for J). The amount of catalyst used in carrying out the process of the invention is between 0.1 and 2% by weight of the monomers to be polymerized. However, it is preferred that the amount of catalyst is between 0.1 and 1% by weight.

According to another method for producing the varnish of the present invention, the above-defined polymer (A) is present in at least one halogenated solvent and/or at least one ketone solvent.
and at least one or more of the polymers (B) defined above. polymer(
B) comprises radical polymerization of at least one fluorinated monomer of formula (I>) and at least one vinyl monomer of formula (II) in the predetermined ratios mentioned above in the presence of a chain inhibitor, for example a mercaptan. It can be obtained by

The varnish of the present invention exhibits excellent adhesion to various thermoplastic and thermoset materials, such as methyl polymethacrylate, ABS resin, and polystyrene.

The dry extract of the varnish according to the invention is 5-50% by weight, preferably 15-30% by weight.

The varnish of the present invention is elastic and has high mechanical strength, so it is particularly resistant to bending tests.

Optionally, adjuvants, such as plasticizers, may be added to the varnishes of the invention. Examples of the plasticizer include phthalates such as dibutyl phthalate and diethyl phthalate.

The varnish according to the invention is applied in a conventional manner.

That is, the varnish is applied by a thermal spray gun or by using a dipping method. It is also possible to use a machine to apply varnish onto a flat board before thermoforming, or to apply varnish onto a thermoformed board.

EXAMPLES The invention may be better understood by the following examples. However, the present invention is not limited to the following examples.

Example 1 The following starting materials (in parts by weight) are introduced into a reaction vessel equipped with a cooling device, a mechanical stirring device, a nitrogen blowing device and a temperature control device.

Monodichloromethane: 150-
2.2.2-trifluoroethyl methacrylate): 100-methacrylic acid: 2-methylmethacrylenite: 1-bis(4-cthiobutylcyclohexyl)beroxydicarbonate)
:0.6 The reaction medium is stirred for 12 hours, keeping the temperature at 40°C. The reaction medium is then cooled to room temperature. The degree of polymerization is 85%. After 8 days, the degree of polymerization reaches 98%. The varnish thus obtained contains 96.6% by weight of polymer (A) with an average molecular weight of 145,000, and 3.4% by weight of polymer (B) with an average molecular weight of 700.
Contains weight %.

A sample piece of methyl polymethacrylate with a width of 25.5 mm, a thickness of 2.9 mm, and a length of 180 mm was coated with approximately 0.3 varnish.
Apply to a thickness of n++n.

Even when 75% by weight sulfuric acid is applied to this sample piece, no deterioration of the varnish layer is observed at all.

In the crack threshold measurement according to the A I R9106A standard in the aviation specifications, cracks were tested over a length of 100 mm and a sample piece to be varnished was tested for 0.79K.
When applying a force of g, the following results are obtained.

・Hi-U discount fLVJ when using Improper tool
'iti: 1.9kg/mm
Increasing threshold when 2.75% by weight sulfuric acid is applied: 2.8kg/mm2 Example 2 In the same reaction vessel as in Example 1, the following monomers are polymerized to produce 100 parts of varnish (unit: parts by weight).

The monomers to be mixed are -2,2,2-trifluoroethyl methacrylate 5-2.2.
2-trifluoroethyl acrylate): 25-methacrylic acid: 2-methyl methacrylate: 1. The polymerization is carried out in the presence of 0.5N bis(4-terthiobutylcyclohexylperoxycarbonate, 150 parts of dichloromethane, and 150 parts of methyl ethyl ketone).

Polymerization is carried out at a temperature of 50° C. for 12 hours. The reaction mixture is then cooled to room temperature and left for 8 days.

The varnish thus obtained has an average molecular weight of 115
．． 000 polymer (A) and 1.2 weight % of polymer (B) having an average molecular weight of 1.200.

This varnish has excellent adhesion to thermosetting and thermoplastic materials and does not deteriorate even in the presence of 75% by weight sulfuric acid.

The results of a crack test conducted under the same conditions as Example 1 are as follows.

- Crack threshold when 75% by weight sulfuric acid is applied 2. "kg/++nn2 Example 3 In the same reaction vessel as in Example 1, the following monomers were polymerized in solution to produce 100 parts of varnish (unit: parts by weight).

The monomers to be mixed are -2,2,2'-trifluoroethyl methacrylate: 100 to methyl methacrylate; 1-methacrylic acid = 2. The polymerization is carried out in the presence of 0.3 parts of bis(4-terthiobutylcyclohexyl) peroxydicarbonate, 0.3 parts of 2.2"-azobisisobutyronitrile, 150 parts of 1,2-dichloroethane, and 150 parts of methyl ethyl ketone. .

Polymerization is carried out at a temperature of 60° C. for 12 hours. The reaction mixture is then cooled to room temperature and left for 8 days.

The varnish thus obtained has an average molecular weight of 50.
000 polymer (A) and 2.5 weight% of polymer (B) having an average molecular weight of 900.

This varnish has excellent adhesion to thermosetting and thermoplastic materials and does not deteriorate even in the presence of 75% by weight sulfuric acid.

The results of a crack test conducted under the same conditions as Example 1 are as follows.

・Crack threshold when Improper tool is applied 1.82kg/mm2・Crack threshold when 75% by weight sulfuric acid is applied
2.8 kg/mm2 Example 4 In the same reaction vessel as in Example 1, the following monoar was polymerized in solution to produce 100 parts of varnish (unit: parts by weight).

The monomers to be mixed are: -methyl methacrylate: 25-2
．． 2.2-Trifluoroethyl methacrylate Near 5-methacrylic acid: 28% acetylcyclohexane sulfonyl peroxide in 2-phthalate: 0.2-bis(4-terthiobutylcyclohexyl) peroxydicarbonate
;0.2. This polymerization was carried out using dichloromethane 150
part and 150 parts of 1°2-dichloroethane.

After polymerization for 12 hours at a temperature of 52° C., the product obtained is left to stand at room temperature for 8 days.

The resulting varnish contains 97.1% by weight of polymer (A) with an average molecular weight of 65,000 and 2.9% by weight of polymer (B) with an average molecular weight of 1,000.

This varnish has excellent adhesion to thermosetting and thermoplastic materials and does not deteriorate even in the presence of 75% by weight sulfuric acid.

The results of a crack test conducted under the same conditions as Example 1 are as follows.

Crack threshold when 75% by weight sulfuric acid is applied: 2.8 kg/mm2 Example 5 (Comparative example) The following charges are introduced into the same reaction vessel as in Example 1 (
Units are parts by weight).

-2,2,2- Trifluoroethyl methacrylate = 100-methyl methacrylate: 1-methacrylic acid: 2-bis(4-terthiobutylcyclohexyl) peroxydicarbonate
:0.6-ethyl acetate
When chromatography is performed by passing through a :150 gel, the resulting chromatogram is a Gauss-type curve with a single peak. This peak has an average molecular weight of 47.0
Corresponds to 00 polymer (A). - The polymerization reaction is carried out at a temperature of 80°C.

When the varnish thus obtained is applied on methylpolymethacrylate, it cracks during the bending test even in the absence of sulfuric acid or impropatol.

Example 6 (comparative example) This example is almost the same as Example 5.

The differences are that the solvent was 1,2-dichloroethane and the temperature of the polymerization reaction was 83.5°C.

When the varnish thus obtained is applied on polymethyl methacrylate, it cracks during the bending test even in the absence of sulfuric acid or impropatul.

When chromatography is performed by transmitting it, the resulting chromatogram is a Gauss-shaped curve with a single peak. This peak is a polymer with an average molecular weight of 8.5.000 (
Corresponds to A).

Patent Applicant: Société Simitsuku Descharbonage Varnish, A.

Claims (11)

[Claims] (1) A protective varnish comprising the following polymers in at least one halogen solvent and/or at least one ketone solvent in the following proportions: - an average molecular weight of 15,000 to 800,000; - 0.1 to 5% by weight of a polymer (B) having an average molecular weight of 500 to 4,000. Polymer (B) is - at least one fluorinated monomer represented by the following chemical formula: H_2C=C(R_1)-C(O)-O--C(R_2)(R_3)-C_nF_2_n_+_1
____mH_m...(I) (However, R_1 is a methyl group, hydrogen atom, chlorine atom, or fluorine atom, and R_2 and R_3 are H, CH_3, CH_2-CH_3
or CF_3, which may be the same or different from each other, n is an integer of 1 to 20, and m is an integer of 0 to 2n) in an amount of 50 to 100% by weight, - at least one vinyl monomer ( A varnish produced by polymerizing 0 to 50% by weight of II). (2) The varnish according to claim 1, wherein the varnish contains 50 to 90% by weight of a halogen solvent and/or a ketone solvent. (3) The average molecular weight of the polymer (A) is 50,000
300,000. The varnish according to claim 1 or 2, wherein (4) The average molecular weight of the polymer (B) is 500 to 2,
Claims 1 to 3 characterized in that: 000
The varnish according to any one of paragraphs. (5) The fluorinated monomer of the above chemical formula (I) is 2,2
, 2-trifluoroethyl methacrylate and/or 2,2,2-trifluoroethyl acrylate. (6) The vinyl monomer of the above chemical formula (II) is replaced with a (meth)acrylic acid monomer such as methacrylic acid, a meth(acrylate) such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, glycidyl methacrylate, or 2 6. The varnish according to claim 1, wherein the varnish is selected from among chlorinated methacrylates such as -chloroethyl methacrylate and 2,2,2-trichloroethyl methacrylate. (7) The varnish according to any one of claims 1 to 6, wherein the ketone solvent is selected from acetone, methyl ethyl ketone, methyl isobutyl ketone, and isophorone. (8) The halogenated solvent is selected from dichloromethane, chloroform, 1,2-dichloroethane, and 1,1-dichloroethane, according to any one of claims 1 to 7. varnish. (9) A method for producing a protective varnish, comprising a temperature of 20 to 70
- at least one fluorinated monomer of the following chemical formula, H_2C=C(R_1)-C(O)-O- -C(R_2)(R_3)-C_nF_2_n_+_1
____mH_m...(I) (However, R_1 is a methyl group, hydrogen atom, chlorine atom, or fluorine atom, and R_2 and R_3 are H, CH_3, CH_2-CH_3
or CF_3, which may be the same or different from each other, n is an integer of 1 to 20, and m is an integer of 0 to 2n) in an amount of 50 to 100% by weight, - at least one vinyl monomer ( A process characterized in that monomers consisting of 0 to 50% by weight of II) are polymerized in solution in the presence of at least one catalyst. (10) The method according to claim 9, wherein the polymerization reaction is carried out at 40 to 60°C. (11) Claim 9 or 10, characterized in that the polymerization reaction is carried out in a halogenated solvent selected from dichloromethane, chloroform, 1,2-dichloroethane, and 1,1-dichloroethane. The method described in.