JP2001031910A - Modifier for coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new type of modifier for a coating, which has a low viscosity and a low volatile content and is excellent in compatibility with a synthetic resin coating (crosslink resin) and in weather resistance, and thereby to improve chemical and physical characteristics of the synthetic resin coating. SOLUTION: There is provided a modifier for a coating comprising a liquid oligomer obtained by copolymerizing styrenes with phenols by an acid catalyst, wherein 0.1-2.0 moles of the phenols are employed relative to 1 mole of the styrenes and the styrenes comprise 0-90 wt.% of styrene and 10-100 wt.% of at least one of α-methylstyrene and p-methylstyrene. The phenol is at least one compound selected from alkylphenols consisting of phenol, naphthol, cresol, tert.-butylphenol, tert.-octylphenol, nonylphenol and the like, and desirably, the viscosity of the liquid elastomer obtained is 0.1-100 P at 25 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating modifier for improving the handling workability, chemical properties, physical properties, etc., of a synthetic resin paint.

[0002]

2. Description of the Related Art Conventionally, a coating modifier has been used for a synthetic resin coating composed of a crosslinked resin such as an epoxy resin or a urethane resin. Paint modifiers can be used in conjunction with synthetic resins to lower the viscosity of the resin composition and improve its handling, or to provide water, chemical, flex and impact resistance,
It improves elongation and tensile strength. Until now, bitumen substances such as coal tar, pitch, swelling charcoal and the like have been frequently used as paint modifiers, but bituminous substances are black and cannot be used for synthetic resin paints for light color. In addition, petroleum resins, coumarone resins, xylene resins, toluene resins and the like are also used, but these have problems in compatibility with the crosslinked resin, weather resistance and the like.

[0003] Recently, attempts have been made to use a liquid low-polymer as a coating modifier, and in particular, focusing on easily available styrene, a coating modifier comprising a liquid oligomer obtained by polymerizing a styrene monomer in the presence of an acid catalyst. Materials have been proposed. This styrene oligomer cannot be used alone due to poor compatibility with the crosslinked resin, and should be mixed with an oligomer obtained by polycondensation of a styrene monomer and formaldehyde with an acid catalyst as well (Japanese Patent Publication No. 5185
2). However, the latter oligomer has a low viscosity but contains a large amount of volatile components, which may cause air pollution problems. Therefore, a method has been proposed in which phenol is added to a styrene monomer, primary polymerization is performed with an acid catalyst, and formaldehyde is further polycondensed with the primary polymer (Japanese Patent Publication No. 5-67668). Although the paint modifier obtained by this method has a reduced volatile component, the obtained resin has a viscosity of 20%.
Since it is as high as ~ 1000 P, there is a problem in workability, and since it is polycondensed with formaldehydes, it contains a methylol group and the like, and is expected to have poor weather resistance and yellow. recent years,
From the viewpoint of global environmental issues and the safety and health of workers, the development of high-solid and solvent-free synthetic resin paints has been demanded, and various liquid resins have been marketed. The timber has not been developed yet.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the chemical and physical properties of a synthetic resin paint, and particularly to have a low viscosity and a low volatile content and compatibility with a synthetic resin paint (crosslinked resin). Another object of the present invention is to provide a new type of paint modifier which is rich in weather resistance and excellent in weather resistance.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted studies on paint modifiers comprising liquid oligomers obtained by copolymerizing styrenes and phenols with an acid catalyst. Partly α
It has been found that by using -methylstyrene and / or β-methylstyrene, an excellent coating modifier capable of achieving the above object can be obtained.

Thus, the present invention relates to a paint modifier comprising a liquid oligomer obtained by copolymerizing styrenes and phenols with an acid catalyst, wherein 0.1% of phenols is added to 1 mole of styrenes. To 2.0 moles, and the styrenes contained 0 to 90% by weight of styrene and α-
It is intended to provide a paint modifier characterized in that at least one of methylstyrene and β-methylstyrene comprises 10 to 100% by weight.

In the coating modifier of the present invention, preferably, the phenol is at least one compound selected from the group consisting of phenol, naphthol, cresol, tert-butylphenol, tert-octylphenol, nonylphenol and the like. The viscosity of the paint modifier according to the invention is sufficiently low that the viscosity of the resulting liquid oligomer is 0.1-100 P (poise) at 25 ° C.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The coating modifier of the present invention comprises a copolymerized oligomer of styrenes (at least part of which uses α-methylstyrene and / or β-methylstyrene) and phenols. 5-6
It is not necessary to further polycondense with formaldehyde as in the paint modifier described in 7668. The present invention is based on the fact that a liquid oligomer having a low viscosity and excellent in compatibility with a coating material, weather resistance, and the like can be obtained only by a one-step copolymerization reaction.

[0009] Styrene-phenol copolymer oligomers as paint modifiers produce styrenated phenols by the introduction of OH polar groups, accelerate the reaction with curing agents, and react with paint components such as epoxy resins by the polar groups. The effect of improving the compatibility of phenol and strengthening the coating film by improving the compatibility is provided. On the other hand, excessive addition of phenol causes the hydrophilic group (OH group)
Therefore, there is a problem that the water resistance is deteriorated and the resin viscosity is significantly increased.

According to the present invention, by adding methylstyrene, a viscosity reduction can be realized even if the amount of phenol is increased, and a paint modifier which has less yellowing of the coating film and is excellent in weather resistance is obtained. Can be The reason why such an effect is exerted has not yet been completely elucidated, but it is considered that methylstyrene has a lower reactivity than styrene, so that the degree of polymerization does not increase and a low-viscosity resin is produced. It is said that yellowing of the coating film is caused by a lower aldehyde generated by a peroxide radical generated by photooxidation of the coating film. Although the hydrogen radical of the styrenated phenol inhibits this radical growth, the styrenated phenol synthesized from methylstyrene and phenol seems to have higher antioxidant properties since it easily releases hydrogen radicals because of the presence of the methyl group.

In the coating modifier of the present invention, the styrene constituting the styrene-phenol copolymer oligomer is styrene: methylstyrene = 0: 100 to 90: 1.
In the range of 0% by weight, at least a part of the styrenes is composed of methylstyrene (α-methylstyrene, β-methylstyrene).

In order to obtain a styrene-phenol copolymer oligomer constituting the coating modifier of the present invention, phenols are used in an amount of 0.1 to 2 mol, preferably 1 to 2 mol, per 1 mol of styrenes (styrene + methylstyrene). 0.1-1.0
Moles (9 to 90 phenols to styrenes by weight)
% By weight). This corresponds to the above-mentioned Japanese Patent Publication 5-676.
68 (the amount of phenol added is 0.1 to 3% by weight), the amount of the phenol is large, but the obtained liquid oligomer is 0.1 to 100 P (10 to 10 P) at 25 ° C.
000 cP) and low viscosity. When the amount of phenols is 0.
If the amount is less than 1 mol, the compatibility of the obtained liquid oligomer with the crosslinked resin is deteriorated, which adversely affects the performance of the coating film. If the amount is more than 2 mol, the water resistance is undesirably reduced.

Styrene constituting the paint modifier of the present invention
Phenols used to obtain phenolic copolymer oligomers are phenol, naphthol, cresol, te
rt-butylphenol, tert-octylphenol, alkylphenol comprising nonylphenol, etc.,
These can be used alone or in combination.

The copolymerization reaction between styrenes and phenols is carried out according to a known method using an acid catalyst. Examples of the acid catalyst include sulfuric acid, aluminum chloride, boron trifluoride, silica alumina, activated clay, ion exchange resin, organic sulfonic acid, and the like, and these can be used alone or in combination. Reaction temperature is 40-200
° C, preferably 80 to 120 ° C. The reaction time is 0.
It is 5 to 10 hours, preferably 1 to 6 hours. Water, an organic solvent such as toluene or xylene may be used as a reaction inhibitor during the copolymerization reaction. After completion of the polymerization, the catalyst is removed by an appropriate method, and unreacted components are removed by a conventional operation such as distillation to obtain a liquid oligomer (mainly a bimolecular polymer and a trimolecular polymer). The coating modifier of the present invention comprising the liquid oligomer thus obtained is a modifier for a synthetic resin coating excellent in light color, low viscosity, low volatile content, and excellent in compatibility with a crosslinked resin.

The coating modifier of the present invention is generally used in a synthetic resin coating in an amount of 10 to 200 parts per 100 parts of crosslinked resin solids.
Parts, preferably 20 to 100 parts. If the proportion is too small, the effect of dilution and modification will be insufficient, and if it is too large, the chemical and physical properties inherent in the synthetic resin paint will be impaired. When blending the paint modifier of the present invention into a synthetic resin paint, other additives,
For example, various pigments, fillers, defoamers, thixotropic agents, and the like, and a solvent can be added as required. In addition, the paint modifier of the present invention is used in addition to a synthetic resin paint, and is also used in a synthetic resin to be used as a floor material, a seal material, a waterproof material, and the like.
Such uses are also included in the present invention.

[0016]

EXAMPLES The following examples are provided to further clarify the features of the present invention, but the present invention is not limited by these examples. Example 1: 167.7 g of styrene monomer, 47.5 g of α-methylstyrene monomer, 37.9 g of phenol,
9.5 g of p-toluenesulfonic acid, 3.1 g of water, and 84.3 g of toluene were charged into a reactor, and the temperature was raised to 90 ° C.
Allowed to react for hours. After the completion of the reaction, the catalyst layer was separated and removed using a separating funnel. The oil layer was neutralized with an aqueous solution of caustic soda, washed with water, and unreacted components were removed by distillation under reduced pressure to obtain 239.4 g of a liquid resin. The obtained resin has a viscosity of 1
7.6 P and a heating residue of 94.6%. When this liquid resin was analyzed by GPC, it was found to be a styrene-phenol oligomer composed of a styrene or methylstyrene bimolecular polymer, trimolecular polymer, mono (di, tri)-(α-benzyl) -phenol, or the like. It was confirmed that. This liquid oligomer was used as a coating modifier sample No. It was set to 1.

The total amount of the methylstyrene monomer (MST) and the styrene monomer (ST) is fixed at the same value as in the above case, but the MST / ST ratio is changed while the sample N
o. A liquid resin was prepared by carrying out the same reaction as in the case of Sample No. 1 of the coating modifier according to the present invention. 2-N
o. And 4.

Furthermore, the pH / pH of styrene (ST) and phenol (PH) alone without using any α-methylstyrene
While changing the ratio of Sample No. By performing the same reaction as in the case of No. 1, a paint modifier sample N for comparison was used.
o. C1-No. C3 was prepared.

The performance of the paint modifier samples as a modifier was evaluated. That is, 11 parts of each modifier sample, 25 parts of Epomic R140-90X, 37 parts of talc, 6 parts of titanium oxide, and 15 parts of thinner were mixed and dispersed as a main agent, and the aliphatic modified polyamine curing agent 6 was added thereto.
Was added immediately before coating, mixed and stirred to prepare a coating composition, and this coating composition was subjected to the following performance tests.

(1) Temperature gradient test A shot-blasted steel plate (150 × 70 × 3.2 mm) was pretreated in accordance with JIS K 5400, and then each of the coating compositions obtained above was applied to about 250 μm and applied at 20 ° C. × 65%
After drying for 7 days in an atmosphere of RH, a test plate was obtained. The coated plate was set in a temperature gradient test apparatus in which the coated surface was in contact with water at 40 ° C. and the back surface was in contact with water at 20 ° C., and the number of days until blistering was observed was evaluated (○: 7 days or more, Δ: 5 to 5 days). 6
Days, x: 4 days or less).

(2) Salt water resistance test A test plate obtained in the same manner as described above was scratched with a cutter knife, immersed in a 3% saline solution at 40 ° C. for 6 months, and evaluated by the width of the strip from the wound surface (（). : 4 mm or less, Δ: 5 to 9 mm,
X: 10 mm or more).

(3) Water resistance test A water resistance test was carried out in the same manner as in the above (2) except that tap water was used at 40 ° C. (○ 2 mm or less, Δ: 3 to 5 mm, ×: 6 mm or more).

(4) Electric resistance test A test plate obtained in the same manner as in (1) was scratched in a cross shape with a cutter knife, a zinc electrode was attached, and the plate was immersed in a 3% saline solution at 40 ° C. for one month. Evaluation was made based on the width of the strip from the cross-cut portion (：: 2 mm or less, Δ: 3 to 8 mm, ×: 9)
mm or more).

(5) Yellowing and Topcoat Adhesion A test plate was obtained in the same manner as in (1) except that a migaki steel plate (150 × 70 × 0.5 mm) was used. For yellowing, the test plate was irradiated with WOM for 50 hours, and the degree of yellowing was measured with a color difference meter (Δb value; ○: less than 5.0; Δ: 5.0 to 7.0).
0, x: 7.0 or more).

After the test plate was exposed outdoors for one month, the same type of paint was applied at 250 μm and then immersed in 3% salt water for one month to conduct a 2 mm × 25 cross-cut test (○: 25, Δ: 24 to 16, ×: 15 or less).

The results of the test are shown in Table 1. C in Table 1
As shown in the results of the comparative paint modifier samples 1 to C3, in the copolymer resin composed of only styrene and phenol, the addition of phenol has the effect of improving the compatibility and the corrosion resistance. However, it can be seen that the amount of phenol must be reduced in order to produce a low-viscosity modifier in which the viscosity of the resin increases significantly due to the increase in phenol.

On the other hand, by adding methylstyrene according to the present invention, a decrease in viscosity can be realized even when the amount of phenol added increases to the same extent (sample N in Table 1).
o. C3 and Sample No. of the present invention. 1 to No. 4 is better understood). Then, the sample Nos. 1
-No. As shown by the results of No. 4, the modified material of the present invention has less yellowing and is excellent in weather resistance.

[0028]

[Table 1]

[0029]Example 2  Sample No. 1 was used as a paint modifier according to the present invention. 5-N
o. 7 was prepared as follows. In addition, for comparison
Sample No. C4-C7 were also prepared. [Sample No. 5] 97.9 g of styrene monomer, α
-Methyl styrene monomer 111.0 g, phenol 4
Sample No. 1 of Example 1 was used except that 4.2 g was used.
By performing the same operation as in Step 1, 243.0 g of a liquid resin was obtained.
The obtained resin had a viscosity of 1060 cP and a heating residue of 9
4.3%.

[Sample No. 6] Sample No. 1 of Example 1 except that 88.4 g of α-methylstyrene and 164.7 g of nonylphenol were used. By performing the same operation as in the case of No. 1, 241.8 g of a liquid resin was obtained. The properties of the obtained resin were a viscosity of 972 cP and a heating residue of 95.0%.

[Sample No. 7] α-methylstyrene 135.1 g, tert-octylphenol 118.0 g
Except that the sample No. of Example 1 was used. The same operation as in the case of 1 was performed to obtain 240.0 g of a liquid resin. The obtained resin had a viscosity of 372 cP and a heating residue of 88.0.
%Met.

[Sample No. C4] A commercially available xylene resin (Nicanol Y-1000; trademark, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as a coating modifier. The viscosity of the resin was 1100 cP, and the heating residue was 91.8%.

[Sample No. C5] A commercially available toluene resin (Generalite 6015; trademark, manufactured by General Petroleum Co., Ltd.) was used as a coating modifier. The viscosity of the resin is 68
cP and the heating residue were 83.1%.

[Sample No. C6] A commercially available liquid petroleum resin (TRE-100; trademark, manufactured by Toho Chemical Co., Ltd.) was used as a paint modifier. The viscosity of the resin is 139 cP,
The heating residue was 90.8%.

[Sample No. C7] Only paint without a paint modifier.

These samples were subjected to a performance evaluation test as a coating modifier in the same manner as in Example 1. Table 2 shows the results. As understood from the results shown in Table 2,
The coating modifier of the present invention has a low viscosity comparable to liquid resins that are commercially available as a coating modifier, and has a low volatile content,
Moreover, compatibility with paint, drying characteristics, corrosion resistance, water resistance,
Also excellent in yellowing and the like.

[0037]

[Table 2]

[0038]

The coating modifier of the present invention has high compatibility with synthetic resin coatings composed of crosslinked resins, high weather resistance and little yellowing, and further has drying properties, corrosion resistance, water resistance, and the like.
Also excellent in adhesion and the like. Since the paint modifier of the present invention has low viscosity and low volatile content, it can be used for high solid type or solventless type synthetic resin paint for the purpose of dilution or modification.

Claims (3)

[Claims] 1. A paint modifier comprising a liquid oligomer obtained by copolymerizing styrenes and phenols with an acid catalyst, wherein the phenols are contained in an amount of 0.1 to 2.0 per mole of styrenes. Mole, and the styrene is 0 to 90% by weight of styrene and at least one of α-methylstyrene and β-methylstyrene is 10 to 1%.
A paint modifier comprising: 00% by weight. 2. The paint modifier according to claim 1, wherein the phenol is at least one compound selected from the group consisting of phenol, naphthol, cresol, tert-butylphenol, tert-octylphenol, nonylphenol and the like. 3. The viscosity of the obtained liquid oligomer is 25 ° C.
The paint modifier according to claim 1 or 2, wherein 0.1 to 100P is applied.