JPH11279232A - Copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolymer having excellent adhesivity to a surface having high polarity such as a metal surface, or the like, hydrophobic properties and heat resistance as well, excellent solubility in a solvent in the case of using the copolymer as a coating material, or the like, and a low content of insoluble component. SOLUTION: In this copolymer comprising a monomer containing an alicyclic skeleton and a monomer of the formula (R is a hydrogen atom or a methyl group) as constituent units, characteristically the average copolymerization composition of the monomer containing the alicyclic skeleton in the copolymer is 30-70 mol.% and that of the monomer of the formula is 30-70 mol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent adhesiveness to highly polar surfaces such as metal surfaces, can effectively impart hydrophobicity and heat resistance, and can be used as a solvent when used as a paint or the like. The present invention relates to a suitable copolymer having good solubility in water and a low insoluble content.

[0002]

2. Description of the Related Art Hitherto, it has been known that a compound having a high polarity has good adhesion to a highly polar surface such as a metal surface due to electrostatic interaction. On the other hand, it is known that compounds having low polarity are excellent in terms of hydrophobicity, and cyclic compounds are excellent in terms of heat resistance. Therefore, a binary copolymer in which a monomer having a high polarity and a monomer having a cyclic structure having a low polarity which are considered to have both properties has been proposed.

[0003] However, when the binary copolymer of such a combination is dissolved in a solvent to be used as a solvent-based paint or the like, unnecessary components of the solvent are generated. There was a bad problem.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to have excellent adhesion to a highly polar surface such as a metal surface, and also have hydrophobicity and heat resistance, and Another object of the present invention is to provide a suitable copolymer having good solubility in a solvent and a small insoluble content when used as a paint or the like.

[0005]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies on the solubility of binary or higher copolymers and found that the monomer having an alicyclic skeleton and the polar monomer have a different polarity. In a copolymer containing a specific monomer having two methylene chains introduced at the α-position of a high γ-lactone as a constitutional unit, the average copolymer composition of both monomers is set to a specific region, so that the metal surface The present inventors have found that a suitable copolymer having good adhesion to a highly polar surface such as a paint, and having good solubility in a solvent for a paint or the like and a small insoluble content can be obtained.

That is, the copolymer of the present invention is a copolymer containing, as constituent units, a monomer having an alicyclic skeleton and a monomer represented by the general formula (1). The copolymer composition of a monomer having an alicyclic skeleton of 30 to 70 mol%
And the copolymer composition of the monomer represented by the general formula (1) is 30 to 70 mol%.

[0007]

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[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The copolymer of the present invention is a binary copolymer or more containing a monomer having an alicyclic skeleton and the monomer represented by the general formula (1) as constituent units.

The monomer having an alicyclic skeleton imparts hydrophobicity and heat resistance to a copolymer containing the monomer as a constituent unit. The monomer having the alicyclic skeleton is not particularly limited, but may be cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentadienyl. At least one selected from the group consisting of (meth) acrylates and substituted products thereof is preferred. Here, the term “substituted product” refers to a product in which at least one of the hydrogen atoms of the cyclic skeleton is substituted with a substituent. Examples of the substituent include a linear or branched alkyl group having 1 to 5 carbon atoms. . Specific examples of the monomer having such an alicyclic skeleton include 1-isobornyl methacrylate, 2-methyl-2-adamantyl methacrylate, cyclohexyl methacrylate, adamantyl methacrylate, tricyclodecanyl methacrylate, and dicyclohexane. Pentadiethyl methacrylate and the like can be mentioned, and these can be used alone or in combination of two or more as needed. In addition, 2-methyl-2-adamantyl (meth) acrylate represented by the following general formula (2) is preferable in that it can effectively impart hydrophobicity and heat resistance to a copolymer obtained by polymerization, and in particular, 2 -Methyl-2-adamantyl methacrylate is preferred.

[0010]

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The (co) polymer of the present invention may contain, as constituent units, a monomer having an alicyclic skeleton and a monomer other than the monomer represented by the general formula (1). Such a monomer is not particularly limited as long as it can be copolymerized with the monomer having an alicyclic skeleton and the monomer represented by the general formula (1). For example, methacrylic acid , Styrene, methyl methacrylate, mevalonolactone methacrylate and the like.

The monomer represented by the general formula (1) is
Specifically, when R in the general formula (1) is a hydrogen atom, 1
-(Γ-butyrolactone-2-yl) ethyl acrylate, and 1-in the case where R in the general formula (1) is a methyl group.
(Γ-butyrolactone-2-yl) ethyl methacrylate.

In the copolymer of the present invention, the copolymer composition of the monomer having an alicyclic skeleton is 30 to 70 mol%, and the copolymer composition of the monomer represented by the general formula (1) is 30 mol%. ~
70 mol%. If the copolymer composition of both monomers deviates from this range, the performance as a coating film will be low. Also,
To provide good balance of adhesion, hydrophobicity and heat resistance,
It is preferable that the copolymer composition of the monomer having an alicyclic skeleton and the monomer represented by the general formula (1) be 40 to 60 mol%.

The weight average molecular weight of the copolymer of the present invention is not particularly limited, but is preferably from 1,000 to 100,
000. If the weight average molecular weight is less than 1,000, the obtained copolymer is inferior in hydrophobicity and heat resistance,
If it exceeds 100,000, the solubility in solvents for coatings and the like deteriorates, which is not preferable.

The method for producing the copolymer of the present invention is not particularly limited, and known solution polymerization, suspension polymerization, emulsion polymerization and the like can be used. Specifically, batch polymerization in which all of the raw material monomers and the like are mixed to start polymerization, in an organic solvent in which a monomer solution in which a monomer or a polymerization initiator is previously dissolved in an organic solvent is kept at a constant temperature, And drop polymerization.

Next, a method of using the copolymer of the present invention will be described. The copolymer solution produced by the above production method is diluted to an appropriate solution viscosity with a good solvent such as tetrahydrofuran or 1,4-dioxane, and then dropped into a large amount of a poor solvent such as methanol or water. To precipitate. Thereafter, the obtained precipitate is separated by filtration and sufficiently dried. This step is called reprecipitation and may be unnecessary in some cases, but is very effective for removing unreacted monomers or polymerization initiator remaining in the polymerization solution. If these unreacted monomers and the like remain as they are, they may adversely affect the storage stability and the appearance of the coating film or the like after being made into a paint or the like.

After that, the dried copolymer powder is dissolved in a solvent for paints or the like. The solvent for this coating or the like is arbitrarily selected depending on the purpose, but the copolymer containing an alicyclic skeleton and a lactone skeleton of the present invention has very different polarities, so that the selection of the solvent is very large. Difficult, and the choice of solvent is more than the solubility of the resin, for example, the uniformity of the coating, appearance,
Alternatively, there are restrictions due to safety and the like.

Examples of solvents for paints satisfying such conditions include ethyl lactate, propylene glycol monomethyl ether acetate, cyclohexanone, diglyme and the like.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Here, “parts” means “parts by weight” unless otherwise specified.

The physical properties of the copolymer were measured by the following methods.・ Weight average molecular weight Gel permeation chromatography (GP
It was determined by C) in terms of polymethyl methacrylate. Chloroform was used as a solvent. Copolymer composition ¹ H-NMR was measured and determined from the integrated intensity ratio. Heavy chloroform was used as a solvent. -Solubility test 1 part of the copolymer was added to 10 parts of ethyl lactate or propylene glycol monomethyl ether acetate, and the mixture was stirred at room temperature for 2 hours, and the state of the solution was observed. -Adhesion test The solution obtained by the solubility test using propylene glycol monomethyl ether acetate was applied to the surface of stainless steel made of SUS304, dried at 120 ° C for 10 minutes, and the state of the coating film was observed. However, if there was any insoluble in the solution obtained in the dissolution test, it was removed and applied to the steel surface.

Example 1 A flask equipped with a nitrogen inlet, a stirrer, a condenser and a thermometer was charged under nitrogen atmosphere with 29.3 parts of 2-methyladamantyl methacrylate (50 mol% based on the total monomer components). ), 1- (γ-butyrolactone-2-yl) ethyl methacrylate 24.8
Parts (50 mol% based on all components of the monomer), 82.5 parts of 1,4-dioxane, 3.8 azobisisobutyronitrile
The temperature of the hot water bath was raised to 80 ° C. while stirring, and polymerization was carried out at that temperature for 8 hours. Then, the obtained reaction solution was diluted about 2-fold with tetrahydrofuran and added dropwise to about 10-fold amount of methanol while stirring, to obtain a white precipitate. The resulting precipitate was filtered off and reduced under reduced pressure at 60 ° C. for about 4 hours.
After drying for 0 hour, 42.8 parts of a copolymer was obtained.

The weight average molecular weight of the obtained copolymer is 1
At 2,000, 1- (γ-butyrolactone-2-yl)
The copolymer composition of the ethyl methacrylate structural units with respect to the total copolymer was 49 mol%. ¹ H- of this copolymer
FIG. 1 shows the NMR chart.

The result of the solubility test of this copolymer in ethyl lactate and propylene glycol monomethyl ether acetate was satisfactory with no insolubles. Also, the results of the adhesion test were good, with no peeling of the coating film surface observed.

Comparative Example 1 In Example 1, 1- (γ
-Butyrolactone-2-yl) ethyl methacrylate 2
39.5 parts of a copolymer was prepared in the same manner as in Example 1 except that 4.8 parts was changed to 21.2 parts of β-methacryloyloxy-γ-butyrolactone (50 mol% based on all components of the monomer). I got

The weight average molecular weight of the obtained copolymer is 1
At 1,000, the copolymer composition of the β-methacryloyloxy-γ-butyrolactone structural unit with respect to the total copolymer was 5
It was 0 mol%. As a result of a solubility test of this copolymer in ethyl lactate and propylene glycol monomethyl ether acetate, insoluble components were observed in all cases. However, as a result of the adhesion test of this copolymer,
Peeling was not observed.

Comparative Example 2 In Example 1, 1- (γ
-Butyrolactone-2-yl) ethyl methacrylate 2
4.8 parts of β-methacryloyloxy-β-methyl-γ
-Butyrolactone 23.0 parts (5 parts based on all monomers)
0 mol%) except that it was changed to 3% in the same manner as in Example 1.
9.5 parts of a copolymer were obtained.

The weight average molecular weight of the obtained copolymer is 1
At 5,000, the copolymer composition of the β-methacryloyloxy-β-methyl-γ-butyrolactone structural unit with respect to the total copolymer was 51 mol%. As a result of a solubility test of this copolymer, a slight insoluble content was observed in ethyl lactate, and an insoluble content was also observed in propylene glycol monomethyl ether acetate. However, as a result of the adhesion test of this copolymer, no peeling or the like was observed.

Comparative Example 3 The procedure of Example 1 was repeated except that the amount of 2-methyladamantyl methacrylate was changed to 46.8 parts (80 mol% based on all components of the monomer).
44.3 was carried out in the same manner as in Example 1 except that the charged amount of (γ-butyrolactone-2-yl) ethyl methacrylate was changed to 10.0 parts (20 mol% based on all components of the monomer).
Parts of the copolymer were obtained.

The weight average molecular weight of the obtained copolymer is 1
At 7,000, 1- (γ-butyrolactone-2-yl)
The copolymer composition of the ethyl methacrylate constituent units with respect to the total copolymer was 22 mol%. As a result of a solubility test of this copolymer in ethyl lactate, some insolubles were observed. As a result of a solubility test for propylene glycol monomethyl ether acetate, insoluble components were observed. As a result of the adhesion test of the copolymer, peeling was observed throughout.

Comparative Example 4 In Example 1, 2-methyladamantyl methacrylate was changed to 11.7 parts (20 mol% based on all components of the monomer), and 1- (γ-butyrolactone-2-yl) was used. ) 40.0 ethyl methacrylate
36.5 parts of a copolymer was obtained in the same manner as in Example 1 except that the amount was changed to 80 parts by weight based on the total amount of the monomers.

The weight average molecular weight of the obtained copolymer is 1
At 6,000, 1- (γ-butyrolactone-2-yl)
The copolymer composition of the ethyl methacrylate constituent units with respect to the total copolymer was 81 mol%. As a result of a solubility test of this copolymer in ethyl lactate, considerable insolubles were observed. In addition, as a result of a solubility test for propylene glycol monomethyl ether acetate, a large amount of insoluble matter was observed. As a result of the adhesion test of this copolymer,
Peeling was not observed.

[0032]

Industrial Applicability The copolymer of the present invention has excellent adhesion to highly polar surfaces such as metal surfaces, and also has hydrophobicity and heat resistance. Since it is a copolymer having good solubility in a solvent and a small amount of insoluble components when used as a coating, it is possible to prevent filter clogging in a filtration step when used in a paint or the like, and to prevent poor appearance of a coating film or the like. it can.

[0033]

[Brief description of the drawings]

FIG. 1 is a ¹ H-NMR chart of a copolymer of Example 1.

Claims (1)

[Claims] 1. A copolymer comprising, as constituent units, a monomer having an alicyclic skeleton and a monomer represented by the general formula (1), wherein the copolymer has a unit having an alicyclic skeleton in the copolymer. The copolymer composition of the monomer is 30 to 70 mol% and the general formula (1)
A copolymer having a copolymer composition of 30 to 70 mol% of a monomer represented by the formula: Embedded image