JPH0753723A - Preparattion of polyester-modified silicone resin - Google Patents

Abstract

PURPOSE:To prepare the subject resin improved in stain resistance by mixing a given polyester resin with a terminal-reactive dimethylpolysiloxane of a given formula and effecting hydrolysis and polycondensation reactions thereof in the presence of a catalyst. CONSTITUTION:100 pts.wt. polyester resin contg. at least 2 hydroxyl groups per molecule is admixed with 0.1-10 pts.wt. terminal-reactive dimethylpolysiloxane of the formula I (wherein R<1> and R<2> are each a 1-6C alkyl; R<3> and R<4> are each a 1-8C alkyl or aralkyl; A is an oxygen atom or a polymethylene group; (a) and (b) are each 2 or 3; and (n) is 3 to 200). If necessary, the resulting mixture may further be admixed with at most 1,000 pts.wt. alkoxysilane and/or alkoxysiloxane of the formula II (wherein R<5> is a 1-8C alkyl, phenyl, or aralkyl; R<6> is a 1-6C alkyl; 0<=C<=2; 0<d<=4; and 0<C+d<=4). Subsequently, a catalyst such as acetic acid is added in an amt. of 0.01 to 5wt.% based on the alkoxysilane, etc. The resulting mixture is subjected to hydrolysis and polycondensation reactions at 50 to 120 deg.C to obtain the objective polyester- modified silicone resin.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyester-modified silicone resin in a simplified process.

[0002]

2. Description of the Related Art Polyester-modified silicone resin has excellent weather resistance and heat resistance, and has the excellent property that discoloration due to heat deterioration is small in the modified silicone varnish. It is used in various fields such as paints for machine mufflers and paints for cooking utensils.

In order to improve the stain resistance of a cured coating film of this polyester-modified silicone resin, it has been conventionally practiced to mix a dimethylsiloxane component with the resin before curing. However, even when such components are mixed, cissing is often generated, stain resistance is deteriorated with time, and stains and stickiness of stains are often recognized.

Therefore, a method has been proposed in which a terminal reactive silicone oil having a dimethylsiloxane unit is reacted with a silanol group or an alcoholic hydroxyl group remaining in the polyester-modified silicone resin to introduce the dimethylsiloxane unit into the modified resin. (US Pat. No. 4,898,
(See No. 772).

[0005]

However, in the above-mentioned prior art methods, the reactivity of the terminally reactive silicone oil having a dimethylsiloxane unit is poor.
Unreacted end-reactive silicone oil remains in the resulting modified resin, and as a result, cissing is still recognized and the appearance of the coating film is poor (whitening of the coating film due to incompatible components). There was a problem.

As for the polyester-modified silicone resin, after a polyester resin is produced from a saturated polybasic acid and a polyhydric alcohol, a hydrolyzed condensate (oligomer or polymer) such as chlorosilane or alkoxysilane is first produced, and then a titanium catalyst is produced. It is produced by subjecting a polyester resin to dehydration or dealcoholization condensation reaction with a metal catalyst such as.

However, the above-mentioned manufacturing method has a problem that the manufacturing process is largely divided into three steps, that is, the polyester resin manufacturing step, the silicone resin manufacturing step and the modifying step, and is complicated.

Further, the obtained polyester-modified silicone resin is cured at a high temperature for a long time or by using a curing catalyst such as a lead catalyst in order to form a cured coating film having optimum hardness and abrasion resistance. There was a need. Heating at high temperature for a long time leads to high cost, and use of a lead catalyst or the like has a problem in safety.

Therefore, an object of the present invention is to provide a polyester-modified silicone resin which is excellent in stain resistance and curability in a simplified process.

[0010]

According to the present invention, (A)
A polyester resin containing at least two hydroxyl groups in one molecule, and (B) the following general formula (1):

[Chemical 2] In the formula, R ¹ and R ² are each an alkyl group having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups or aralkyl groups having 1 to 8 carbon atoms, and A is an oxygen atom or a formula:
- (CH _{2) p} - polymethylene group (p is an integer of 2 to 10) represented by, a and b are each 2 or 3, n is an is, in represented integer of 3 to 200 Provided is a method for producing a polyester-modified silicone resin, which comprises mixing a terminal-reactive dimethylpolysiloxane and performing a hydrolysis and a polycondensation reaction in the presence of a catalyst.

In the present invention, the above-mentioned catalyst is used to accelerate hydrolysis, and aliphatic or aromatic carboxylic acid or carboxylic acid anhydride is preferably used.

In addition to the above components (A) and (B), (C) an alkoxysilane or an alkoxysiloxane which is a partial hydrolysis-condensation product thereof may be mixed and used for the reaction in order to adjust the physical properties of the silicone resin. it can.

[0013]

In other words, in the present invention, the terminal reactive dimethylpolysiloxane (component (B)) and the optionally used alkoxysilane or alkoxysiloxane (component (C)) are hydrolyzed and their hydrolysis products are combined with each other. Since the generation of the silicone resin by the condensation polymerization and the modification by the condensation polymerization of the silicone resin and the polyester resin (the condensation polymerization of the silanol group in the silicone resin and the hydroxyl group in the polyester resin) are continuously performed in one step, The manufacturing process is significantly simplified, which is extremely advantageous industrially.
Since the end-reactive dimethylpolysiloxane used for imparting stain resistance and slip resistance has extremely high reactivity, there is almost no risk of this component remaining as an unreacted component, and cissing caused by the remaining component It is possible to effectively avoid the occurrence of white spots and whitening of the coating film.

The catalyst promotes the hydrolysis of terminally reactive dimethylpolysiloxane and alkoxysilane. When an aliphatic or aromatic carboxylic acid or carboxylic acid anhydride is used as the hydrolysis catalyst, Since these are condensed with the hydroxyl group or silanol group in the modified resin and taken into the resin, it is not necessary to neutralize them. Generally, when a hydrolysis catalyst is used, the storage stability of the resin is impaired if the catalyst is present in the product resin in a free state. Therefore, the catalyst is removed by means such as neutralization. However, the present invention is extremely advantageous in that it does not require such a neutralization treatment step at all.

Furthermore, the polyester-modified silicone resin produced by the method of the present invention has significantly improved stain resistance in connection with the introduction of the dimethylpolysiloxane unit into the main chain, and the long-term Thus, the occurrence of stains on the cured coating film or the sticking of stains can be effectively prevented. In addition, it has excellent curability compared to polyester-modified silicone resin produced by conventional methods,
It has an unexpected advantage that a coating film having high hardness and bending strength can be formed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Polyester Resin In the present invention, the polyester resin used as a modifier of the silicone resin is a conventionally known one, and has at least two hydroxyl groups in one molecule. What is contained is used. That is, the silicone resin is modified by condensing the hydroxyl group with the silanol group in the silicone resin. Such polyester resins are usually easily obtained by esterification of saturated polybasic acids with polyhydric alcohols.

As the saturated polybasic acid, for example, isophthalic acid, terephthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, adipic acid and the like can be used alone or in combination of two or more kinds. As the polyhydric alcohol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, neopentyl glycol, trimethylolethane, trimethylolpropane, etc. can be used alone or in combination of two or more.

The ratio of the saturated polybasic acid and the polyhydric alcohol used in the esterification reaction is set so that the polyester resin to be formed has at least two hydroxyl groups in one molecule. Is used in an amount such that the OH groups of the polyhydric alcohol are in excess of the COOH groups of, for example, a ratio of 1.02 to 3.00 mol of OH groups per 1 mol of the COOH groups. Thereby, the acid value of the obtained polyester resin is usually 10 or less, preferably 5 or less.

The molecular weight of the polyester resin used is appropriately determined according to the characteristics of the desired modified silicone resin. Further, the polyester resin may be a solid one, but it is usually diluted with a solvent to about 50 to 95%,
It is suitable to be used for the reaction with an alkoxysilane described below. Examples of such a solvent include cellosolve solvents such as cellosolve acetate, glycol solvents such as propylene glycol, hydrocarbon solvents such as xylene, and the like.
The alcohol-based, ester-based, and ketone-based solvents are used alone or as a mixed solvent in which two or more kinds are mixed.

(B) End-Reactive Dimethyl Polysiloxane The end-reactive dimethyl polysiloxane is used for improving the sliding property and peeling property of the coating film and enhancing the function of preventing the adhesion of stains and the like. This polysiloxane is
It is represented by the general formula (1), and as can be understood from the fact that a and b in the formula are 2 or 3, it has many functional groups (alkoxy groups) at both ends of the molecular chain. Therefore, it is reliably incorporated into the resin and does not remain as an unreacted component. Therefore, problems such as cissing and poor appearance can be effectively solved.

[0021] In the general formula (1), A represents an oxygen atom or the following _{formula: - (CH 2) p -} (p is an integer of 2 to 10) is a polymethylene group represented by is preferably a polymethylene group , Most preferably a dimethylene group (p = 2 in the above formula). That is, by introducing a methylene chain into the main chain, the reactivity of the terminal functional group is improved, and the dimethylpolysiloxane unit is more reliably introduced into the modified resin.

R ¹ and R ² are alkyl groups having 1 to 6 carbon atoms, preferably methyl groups. R ³ and R ⁴ are aralkyl groups having 1 to 8 carbon atoms such as an alkyl group, a benzyl group and a phenylethyl group, and preferably a methyl group. In addition, n, which is a measure of the degree of polymerization
Is an integer of 3 to 200.

Suitable examples of such a terminal-reactive dimethylpolysiloxane include the following due to their ease of synthesis.

[0024]

[Chemical 3]

The above-mentioned end-reactive dimethylpolysiloxane can be produced by a method known per se, for example, in the presence of a platinum catalyst, the following formula:

[0026]

[Chemical 4]

By adding reaction of vinyltrimethoxysilane or vinylmethyldimethylsilane to the methylhydrogenpolysiloxane represented by or addition reaction of dimethylpolysiloxane having vinyl at both ends with trimethoxysilane or dimethylmethylsilane. It is obtained by

In the present invention, such an end-reactive dimethylpolysiloxane is a polyester (A) component 10
It is preferably used in an amount of 0.1 to 10.0 parts by weight, particularly 0.5 to 5 parts by weight, based on 0 part by weight. If it is less than 0.1 part by weight, it becomes difficult to improve the stain resistance, and if it is used in a larger amount than 5 parts by weight, unreacted components are increased, and the unreacted components may cause cissing on the cured coating film. It tends to cause whitening and the like.

(C) Alkoxysilane and Alkoxysiloxane In the present invention, an alkoxysilane and / or an alkoxysiloxane which is a partial hydrolyzed condensate thereof can be used at the same time as the component (B). These alkoxysilanes and the like are simultaneously hydrolyzed and condensed with the component (B) to form a silicone resin skeleton. These are, for example, the following general formula (2): (R ⁵ ) _c (OR ⁶ ) _d SiO _{[4- (c + d)] / 2} (2) In the formula, R ⁵ has 1 to 8 carbon atoms. At least one group selected from the group consisting of an alkyl group, a phenyl group and an aralkyl group, R ⁶ is an alkyl group having 1 to 6 carbon atoms, and c and d are 0 ≦ c ≦ 2, 0 < d ≦ 4, and 0 <
It is represented by a number satisfying c + d ≦ 4.

In the general formula (2), R ⁵ and R
Each group of ⁶ is as described above, each group may be the same or a combination of different groups from each other, particularly when heat resistance is required or when compatibility with a polyester resin is required. It is preferred that R ⁵ contains at least a phenyl group. In this case, it is natural that c> 0.

Typical examples of the alkoxysilane used in the present invention include, but are not limited to, the followings.
They may be used alone or in combination of two or more.

CH ₃ Si (OCH ₃ ) ₃ , CH ₃ Si
(OC ₂ H ₅ ) ₃ , C ₆ H ₅ Si (OCH ₃ ) ₃ , C ₆
H ₅ Si (OC ₂ H ₅ ) ₃ , (CH ₃ ) ₂ Si (OCH
₃ ) ₂ , (CH ₃ ) ₂ Si (OC ₂ H ₅ ) ₂ , (C ₆ H
₅ ) ₂ Si (OCH ₃ ) ₂ , (C ₆ H ₅ ) ₂ Si (OC
₂ H ₅ ) ₂ , Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ )
_4th grade.

Typical examples of the alkoxysiloxane are partial hydrolysis-condensation products of the above-mentioned alkoxysilanes, for example, tetramers or less, particularly 2 to 4 on average.
Oligomers of about the tetramer are suitable.

These silanes and siloxanes are usually 1,000 parts by weight or less, preferably 20 to 1,000 parts by weight, particularly 50 parts by weight, based on 100 parts by weight of the polyester resin solid content, depending on the physical properties of the intended modified resin. Used in amounts of up to 800 parts by weight.

(D) Catalyst The catalyst used in the present invention is used in order to accelerate the hydrolysis of the above-mentioned terminally reactive dimethylpolysiloxane and alkoxysilane or alkoxysiloxane, and is particularly preferably aliphatic or Aromatic carboxylic acids and acid anhydrides, especially those soluble in water or alcohol at 50 ° C. or lower are preferably used. Typical examples are oxalic acid, lactic acid, acetic acid, malic acid, adipic acid,
Maleic acid, phthalic acid, benzoic acid, maleic anhydride,
Examples thereof include phthalic anhydride and benzoic anhydride.

That is, these catalysts promote hydrolysis of the alkoxysilane and the like, and react with hydroxyl groups or silanol groups in the resulting modified resin to be incorporated into the resin, so that they are neutralized. It is extremely advantageous in that it does not need to be removed by. In this case, when a monocarboxylic acid is used, the monocarboxylic acid incorporated in the modified resin will be present at the molecular end,
Most preferred among the above are polybasic acids and their acid anhydrides, since the stability of the resin may be impaired.

In the present invention, in addition to the above, it is possible to use, for example, an acid catalyst such as hydrochloric acid, sulfuric acid, nitric acid or methanesulfonic acid, an alkali catalyst, etc. In order to improve the storage stability of the resin, it is troublesome that the residual catalyst must be removed by neutralization.

In the present invention, the above-mentioned catalyst is (B)
It is preferably used in an amount of 0.01 to 5% by weight, particularly 0.1 to 1% by weight, based on the component alkoxysilane or alkoxysiloxane.

Hydrolysis and polycondensation reaction According to the present invention, the above-mentioned components are mixed to carry out hydrolysis and polycondensation reaction. That is, the hydrolysis reaction of the terminal-reactive dimethylpolysiloxane and, if necessary, the alkoxysilane or alkoxysiloxane used, proceeds first, and subsequently, the production of the silicone resin by the condensation polymerization of the produced hydrolysates, and the production thereof. The polycondensation reaction between the silicone resin and the polyester resin proceeds in parallel, and the polyester-modified silicone resin is obtained in one step.

The hydrolysis reaction that triggers these reactions is started by adding water to the reaction system. The blending amount of water is preferably 0.8 to 2.0 mole times the theoretical amount required to silanolize all the alkoxy groups in the components (B) and (C).

Mixing of the respective components prior to the hydrolysis reaction may be carried out in various solvents such as a suitable solvent such as cellosolve solvent, propylene glycol solvent, hydrocarbon solvent, alcohol solvent, ester solvent, ketone solvent and the like. It is desirable to use the above solvent, but it is preferable to use at least a part of an alcohol solvent such as isopropyl alcohol in order to uniformly disperse water. Further, the various solvents described above can also be used as a diluent for the resin produced after the reaction.

The hydrolysis reaction and the subsequent reaction are generally preferably carried out at a temperature of 50 to 120 ° C., and usually the reaction is completed in about 1 to 10 hours. After completion of the reaction, the condensation water is distilled off, and if necessary, the above-mentioned various solvents are used as diluents to obtain a polyester-modified silicone resin solution having an appropriate concentration.

Such a modified silicone resin is cured by heating to form a coating film excellent in stain resistance and slipperiness, for example, as a paint used for building materials, cooking utensils, etc. It is extremely useful as a coating agent for applying.

[0044]

EXAMPLES In the following examples, "parts" means "parts by weight", and viscosities are measured values at 25 ° C.

Production of polyester resin A stirring device equipped with a thermometer and a reflux condenser was charged with 48 parts of trimethylolethane, 12 parts of 3-methyl-3-methoxybutylacetate and 2.4 parts of water, and the mixture was heated to 90 ° C. The temperature was raised to dissolve trimethylolethane. Next, 49.8 parts of isophthalic acid and 2.2 parts of xylene were added, the mixture was kept at 220 ° C. for 24 hours, water and alcohol were distilled off, and then 3-methyl-3-methoxybutylacetate 37.3 parts was added to obtain an acid value. 3. A polyester resin solution having a nonvolatile content of 70% and a viscosity of 10,000 centipoise was obtained.

Example 1 In a stirrer equipped with a thermometer and a reflux condenser,

[0047]

[Chemical 5] 42.0 parts of disiloxane

[0048]

[Chemical 6] 13.6 parts of disiloxane represented by

The following average formula:

[Chemical 7] 0.8 parts of a terminal alkoxypolysiloxane represented by

Polyester resin produced above 18.7
Parts, water 7.6 parts, propylene glycol monomethyl ether acetate
Charge 32.3 parts, isopropyl alcohol 2.1 parts, maleic anhydride 0.21 parts and reflux for 1 hour, then raise the temperature to 120 ° C. while distilling off alcohol and water to obtain propylene glycol monomethyl ether acetate.
18.7 parts of was added to obtain a polyester-modified silicone resin having a nonvolatile content of 60% and a viscosity of 200 cSt. This resin was applied onto a mild steel plate using a bar coater No. 36, air-dried for 30 minutes, and then dried for 150 minutes.
It was cured at 30 ° C. for 30 minutes to form a cured coating film. The coating properties are shown in Table 1.

Example 2 Instead of the terminal alkoxypolysiloxane used in Example 1, the following average formula:

[Chemical 8] A polyester-modified silicone resin was prepared in the same manner as in Example 1 except that 0.8 part of the terminal alkoxypolysiloxane represented by was used, and the cured coating film was formed. The coating properties are shown in Table 1.

Comparative Example 1 A polyester-modified silicone resin was prepared and a cured coating film was formed in the same manner as in Example 1 except that no terminal alkoxypolysiloxane was used. The coating properties are shown in Table 1.

Comparative Example 2 Polyester-modified silicone resin 1 obtained in Comparative Example 1
3 parts of Pb (OOCC ₇ H ₁₅ ) ₂ (Pb content 24%) was mixed with 00 parts, and the mixture was cured under the same conditions as in Example 1 to obtain a cured coating film. The coating film physical properties are shown in Table 1.

[0054]

[Table 1]

The test methods for each physical property were as follows. Pencil hardness: Measured according to JIS K-5400 Item 6-14. Eyelet adhesion: Measured according to JIS K-5400, item 6-15. Mandrel test: Measured according to JIS K-5400 Clause 6-16 (using 2mmφ mandrel) Impact resistance test: Measured according to JIS K-5400 Clause 6-13 (Use 1/2 inch steel ball) The load is measured at 100g) Dynamic friction coefficient: Measured with KYOWA'S DF-PM APPARATUS (Kyowa Scientific Co., Ltd.) Peeling force: Cellophane tape (Nichiban) is attached to the coating surface to prepare a sample, and immediately after that, a tensile tester is used. Using the tape, the tapes that were stuck together were peeled off at an angle of 180 ° and a peeling speed of 0.3 m / min, and the force required for peeling (g / 18 mm) was measured. Contamination resistance: The coating film was marked with an oil-based marker (made by Pentel), air-dried for 24 hours, and lightly wiped with absorbent cotton impregnated with isopropanol to visually judge the appearance.

[0056]

According to the present invention, since the steps of hydrolysis, polycondensation and modification are carried out in a continuous one-step reaction,
The polyester-modified silicone resin can be obtained in a smaller number of steps than the conventional method. In particular, since the end-reactive polysiloxane component used for imparting stain resistance and the like does not remain in an unreacted state, cissing occurs on the cured coating film formed and whitening occurs. Nothing. The obtained resin has good stain resistance and slipperiness, effectively prevents adhesion of dirt and stickiness over a long period of time, and has excellent curability, and is a curing catalyst with a safety problem such as a lead catalyst. It is possible to form a cured coating film having excellent mechanical properties even under mild curing conditions without using.

Claims (6)

[Claims] 1. (A) A polyester resin containing at least two hydroxyl groups in one molecule, and (B) the following general formula (1): In the formula, R ¹ and R ² are each an alkyl group having 1 to 6 carbon atoms, R ³ and R ⁴ are alkyl groups or aralkyl groups having 1 to 8 carbon atoms, and A is an oxygen atom or a formula:- (CH ₂ ) _p − (p is 2
An integer of 10 to 10), a and b are each 2 or 3, and n is an integer of 3 to 200. A method for producing a polyester-modified silicone resin, which comprises performing a hydrolysis and a polycondensation reaction in the presence of a catalyst. 2. The production method according to claim 1, wherein the terminal-reactive dimethylpolysiloxane is one in which A in the general formula (2) is a dimethylene group. 3. Simultaneously with the components (A) and (B),
The production method according to claim 1, wherein (C) an alkoxysilane or an alkoxysiloxane which is a partial hydrolysis-condensation product thereof is mixed and subjected to the reaction. 4. As the alkoxysilane and / or alkoxysiloxane, the following general formula (2): (R ⁵ ) _c (OR ⁶ ) _d SiO _{[4- (c + d)] / 2} (2) wherein R ⁵ is at least one group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, a phenyl group and an aralkyl group, R ⁶ is an alkyl group having 1 to 6 carbon atoms, c and d Is 0 ≦ c ≦ 2, 0 <d ≦ 4, and 0 <c + d
The manufacturing method according to claim 4, wherein a number represented by ≦ 4 is used. 5. The process according to claim 1, wherein an aliphatic or aromatic carboxylic acid or carboxylic acid anhydride is used as the catalyst. 6. A polyester-modified silicone resin obtained by the method according to claim 1.