JPS6096659A - Paint composition - Google Patents

Abstract

PURPOSE:To obtain paint which has excellent workability without requiring any pretreatments such as sanding, by blending a chlorinated rubber and hygroscopic silica with an alkyd resin. CONSTITUTION:10-50pts.wt., pref. 20-30pts.wt. chlorinated rubber and 1-10pts. wt., pref. 3-7pts.wt. hygroscopic silica are blended with 100pts.wt. alkyd resin. The alkyd resin can be prepared by modifying a polyester obtd. from the reaction between a polyhydric alcohol and a polybasic acid, with a modifier. Examples of such modifiers are fatty acids such as coconut oil fatty acid and soybean oil fatty acid. Examples of the alkyd resins serving as a base paint are room-temperature drying type resins having an oil length of 30-50% such as styrenated alkyd resin and phenol-modified alkyd resin. The term ''oil length'' used herein refers to the content (wt%) of the fatty acid used as the modifier.

Description

[Detailed description of the invention] [Technology distribution] The present invention relates to a coating composition with excellent adhesion.

In order to ensure that the paint adheres to the adherend, complicated pretreatment operations such as sanding the adherend to remove rust and cleaning with a solvent are necessary.

[Prior Art] As a coating composition with good adhesion that does not require pre-treatment before painting, JP-A-49-97022 discloses a coating composition composed of a specific polyester, a polyisocyanate, and a pigment. Coating compositions that can be coated without requiring surface treatment of adherents have been reported. Furthermore, since non-sanding coating is difficult, Japanese Patent Publication No. 49-33590 discloses a wet-on-wet method for improving the base coating to make it easier to sand.

[Object of the Invention] An object of the present invention is to provide a coating composition with excellent adhesion that does not require pretreatment operations such as sanding.

[Structure of the Invention] The coating composition of the present invention contains 100 parts by weight or less of an alkyd resin, where parts mean parts by weight. ) to chlorinated rubber 10
~50 parts by weight, and 1~10 parts of hygroscopic silica.

[Detailed Description of the Structure of the Invention] The alkyd resin constituting the main component of the coating composition of the present invention is synthesized by performing various modifications using a modifier using a polyester of a polyhydric alcohol and a polybasic acid as the main reaction. Ru. As the polyhydric alcohol, glycerin, pentaerythritol, etc. are used, and as the polybasic acid, phthalic anhydride, isophthalic acid, etc. are used. Various fatty acids (coconut oil fatty acids, safflower fatty acids, soybean fatty acids, linseed fatty acids, etc.) are used as modifiers.Alkyd resins are the base of paints, and air-drying types such as styrenated alkyd resins and phenol-modified alkyd resins are used. Oil length 30-50%
is appropriate. Here, the oil length refers to the content ft (% by weight) of the fatty acid used as a denaturing agent. Yucho 3
The range of 0 to 50% was set in consideration of the water resistance, hardness, and gloss of the coating film.

The chlorinated rubber that characterizes the coating composition of the present invention is one in which chlorine is introduced into the double bond of natural rubber or synthetic rubber.
Molecular weight is about 5000 to 1000 parts, specific gravity is about 1.6,
Preferably, the chlorine content is about 65% or more. Chlorinated rubber obtained by chlorinating atactic polypropylene, ethylene propylene rubber, etc. can be used as long as the properties are the same.

Chlorinated rubber increases the tackiness of the coating composition and improves its affinity for adherends. In addition, chlorinated rubber plays a role such as relieving residual stress during coating film formation, and solves problems such as peeling of the formed coating film from the adherend.

Hygroscopic silica refers to extremely pure silicon dioxide, where L' is a particle diameter of 10 to 40μ and a specific surface area of 50 to 400.
It is preferable to have a silanol group or the like on the surface by surface treatment of about 1/g.

The hygroscopic silica has the effect of increasing the resistance f1 against environmental changes when worn, and makes it possible to always apply the desired coating even under temperature and humidity changes during coating.

The coating composition of the present invention may contain components other than those mentioned above, such as inorganic fillers, tackifiers, pigments, ultraviolet absorbers, anti-settling agents, and anti-skinning agents.

The blending ratio of the components of the coating composition of the present invention is 10 to 50 parts, more preferably 20 to 30 parts of chlorinated rubber per 100 parts of alkyd resin. In addition, hygroscopic silica is 1
~10 parts, more preferably 3 to 7 parts.

[Effects of the Invention] The coating composition of the present invention has extremely high adhesion due to the combination of chlorinated rubber and hygroscopic silica, and can be directly applied to adherends without pretreatment such as sanding or cleaning.

In particular, the coating composition of the present invention is outstanding as a coating for non-sanding coating on coatings.

[Example] A paint having the following composition was prepared by diluting it with Kijiroll for 1 hour using a sand grinder to a viscosity of about 20 seconds using a Ford Utsubu viscometer.

Styrenated alkyd resin 100 parts Carbon black 8 parts Chlorinated rubber 20-30 parts Hygroscopic silica 3-7 parts Dryer 1 part Kijiroll 200 parts In addition, as a comparative paint, the following composition containing no chlorinated rubber and hygroscopic silica was used. Paints were prepared in the same way.

Styrenated alkyl 1ζ resin 100 parts Carbon black 8 parts Dryer 1 part Kijiroll 200 parts Using these paints, paint onto the surfaces of metallic color coated plates and solid color coated plates as adherends using the air spray method, and leave them at 100°C for 15 minutes. After forced drying, it was left at room temperature for 72 hours to form a coating film.

Next, in order to check the adhesion of the obtained coating film, JISK54
A peel test was carried out as specified in 00.

In addition, pencil hardness was measured as a representative of other physical property values.

The measurement results obtained and the blending ratios of chlorinated rubber and hygroscopic silica in each paint are shown in the table.

From the table, it can be seen that the paints No. 1 to No. 9 containing chlorinated rubber and hygroscopic silica had high adhesion in 70 or more of the 100 substrate holes.

On the other hand, in paint No. 10 of Comparative Example, 60 or more of the 100 substrates peeled off.

Furthermore, the pencil hardness did not change significantly due to the addition of chlorinated rubber and hygroscopic silica.

Patent applicant: Aisin Kako Co., Ltd. Agent: Patent Attorney Hiroshi Okawa Same patent attorney Jo Fujitani Same patent attorney Akio Maruyama

Claims (3)

[Claims] (1) A coating composition comprising 10 to 50 parts by weight of chlorinated rubber and 1 to 10 parts by weight of hygroscopic silica per 100 parts by weight of alkyd resin. (2) Chlorinated rubber 2 for 100 parts by weight of alkyd resin
The paint and Wl composition according to claim 1, which contains 0 to 30 parts by weight of hygroscopic silica and 3 to 7 parts by weight of hygroscopic silica. (3) Alkyd resins are air-dry types such as styrenated alkyd resins and phenol-modified alkyd resins with an oil length of 30 to 5.
The coating composition according to claim 1, which contains 0%.