JPS632990B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to coating compositions, and in particular to coating compositions suitable for use in electrostatic flocking products. In recent years, electrostatic flocking products have been applied to various fields, but depending on the usage, various performances are required, and conventional flocking products do not necessarily meet these requirements sufficiently. I wasn't satisfied. For example, to explain electrostatic flocking products applied to automobile windows, when supporting the window glass and window frame, especially when the glass can be slidably opened and closed, the frictional resistance Requires a glass holder made of low quality material. In automobiles, window frame rubber, that is, a weather strip made of rubber or plastic, is used to fix the window glass and window frame, and the sliding contact with the sliding glass is used in the parts where the glass slides. Grass run is used in which short fibers are electrostatically flocked. Electrostatic flocking products used as glass runs for automobiles have a particularly high performance in high-temperature atmospheres, weather resistance, heat resistance, etc. compared to electrostatic flocking products used for interior decoration, daily necessities, and dependent items. Various performances are required under various conditions. However, conventional products do not show sufficient performance, especially in terms of abrasion resistance after heat aging, abrasion resistance after weathering, and abrasion resistance in high-temperature atmospheres. The performance improvement is
This was one of the challenges in this technical field. As a result of various studies, the present inventor focused on the fact that in electrostatic flocking products, the paint applied to the flocked areas is the biggest factor in determining the quality of their performance. We have succeeded in providing an inventive coating composition. The coating composition of the present invention is characterized in that it uses a urethane prepolymer described below as a main ingredient, and a specific curing agent and polydimethylpolysiloxane are blended therein. The coating composition of the present invention will be explained in detail below. The urethane prepolymer used as the main ingredient in the coating composition of the present invention is composed of a polyhydroxypolybutadiene (a) in which 98% or more of double bonds are hydrogenated, a polyol (b), and a diisocyanate (c) in equivalent amounts (a) + (b). )
This is a urethane prepolymer having a hydroxyl group at the end obtained by reacting at a ratio of >(c). Here, we will explain polyhydroxypolybutadiene in which 98% or more of double bonds are hydrogenated.
This polyhydroxypolybutadiene is a polybutadiene polymer having one or more hydroxyl groups, preferably 1.8 to 5.0 hydroxyl groups in one molecule, and the average molecular weight is usually 500 to 50,000, preferably 1,000 to 5.0.
20,000, and the manufacturing method thereof is not specified, but various known methods can be employed. For example, in the polymerization of butadiene, hydrogen peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, azobis compounds having functional groups such as β'-azobis(β-cyano)-n-propanol, δ・δ-azobis(δ
Radical polymerization may be carried out in a catalyst such as alcohol, ketone, or ester using a radical polymerization initiator containing a hydroxyl group such as -cyano)-n-pentanol, or aliphatic azodicarboxylic acid or its ester, etc. There is also a method in which polyhydroxypolybutadiene is obtained by similarly polymerizing with a radical polymerization initiator and then reducing the carboxyl group or ester moiety. Alternatively, anionic polymerization may be performed using an alkali metal such as sodium or lithium or a complex of an alkali metal and a polycyclic aromatic compound as a catalyst, followed by functionalization with alkylene oxide, epichlorohydrin, or the like. The catalysts used for anionic polymerization are lithium complexes such as naphthalene complexes, anthracene complexes, and biphenyl complexes, or 1,4-dialkali metal butanes, 1,5
-Dialkali metal pentane, 1,10-dialkali metal decane, 1,4-dialkali metal, 1,1,
Mention may be made of dialkali metal hydrocarbons such as 4,4-tetraphenylbutane. Furthermore, in order to smoothly proceed with such anionic polymerization, a hydrocarbon solvent such as hexane, heptane, benzene, toluene, xylene, cyclohexane, etc. is used. However, when an alkali metal is used as a catalyst, it is preferable to use the above solvent together with a Lewis base such as diethyl ether, dipropyl ether, ethyl propyl ether, ethyl butyl ether. Polyhydroxybutadiene can be obtained by reacting the living polymer thus obtained with an epoxy compound according to a conventional method, and then treating it with a protic acid such as hydrochloric acid, sulfuric acid, or acetic acid. Epoxy compounds used here include monoepoxy compounds such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide, and phenyl glycidyl ether: glycidyl ether of bisphenol A, vinyl cyclohexene diepoxide, butadiene diepoxide, Polyepoxy compounds such as dicyclopentadiene diepoxide, limonene diepoxide, and ethylene glycol bisepoxide; haloepoxy compounds such as epichlorohydrin, epipromhydrin, and methylepichlorohydrin can be used.
More preferred are polyepoxy compounds and haloepoxy compounds. In the case of monoepoxy compounds, the amount used is
Equimolar ratios, especially 2 or more molar ratios to the polymer are preferred. At this time, at both ends of the living polymer,
It is thought that the epoxy compound is bonded in a ring-opened manner, and the hydrogen atom of the ring-opened hydroxy group is substituted with an alkali metal. On the other hand, when using a polyepoxy compound or a haloepoxy compound, it is selected appropriately depending on the intended use of the resulting polymer, that is, the molecular weight and number of hydroxyl groups of the polymer, but it is usually used for living polymers.
A molar ratio of 0.5 to 2.0, preferably 0.6 to 1.0 is used. At this time, after ring-opening of the epoxy, living polymers are mainly bonded to each other to obtain a polymer in which several molecules are bonded via an epoxy compound having a hydroxyl group substituted with an alkali metal. Polyhydroxy,
Polybutadiene can be obtained. The microstructure of the obtained polyhydroxypolybutadiene depends on the manufacturing method, including 1, 2-bonds and 1, 2-bonds.
Polymers having various proportions of 4-bonds are obtained. For example, the microstructure of polyhydroxypolybutadiene produced using a radical polymerization method is 5 to 30% cis-1,4 bonds, 50 to 80% trans-1,4 bonds, and 15 to 30% 1,2 bonds. , and usually has a microstructure with many 1 and 4 bonds. Furthermore, in the anionic polymerization method, polyhydroxypolybutadiene with many 1,4-bonds can be obtained by selecting the type of catalyst and solvent used. The hydrogenated polyhydroxypolybutadiene used in the present invention is obtained by hydrogenating the double bonds in the main chain and/or side chain of the polyhydroxypolybutadiene produced in this way while retaining the hydroxyl groups. You can get it. Hydrogenation catalysts include nickel, cobalt, chromium, copper,
Palladium, platinum, rhodium, osmium, ruthenium, rhenium and the like are generally used, with nickel and ruthenium being preferred. These various metal catalysts are used as the metal itself, as a heterogeneous catalyst supported on a carrier, or as a homogeneous catalyst in which the metal is a soluble salt. As the above-mentioned carrier, carbon, alumina, silica, alumina-silica, diatomaceous earth, barium carbonate, calcium carbonate, etc. are used. In this case, the amount of the above metal supported on the carrier is usually 0.01 to 50% by weight.
It is preferably 0.2 to 15% by weight. Although polyhydroxypolybutadiene can be reacted as it is with hydrogen using the above-mentioned metal as a catalyst, a better hydrogenation reaction can be carried out by using a solvent. As this solvent, aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, ethers, or mixed solvents thereof can be used. The amount of the above-mentioned catalyst used during hydrogenation varies depending on the type of catalyst, hydrogenation type, etc., but for example,
When carrying out suspension polymerization using a ruthenium catalyst,
The ratio of ruthenium to polyhydroxypolybutadiene is used in the range of 0.01 to 1.00% by weight. The reaction temperature is preferably 20 to 150°C. If the reaction temperature becomes high, the hydrogenation rate can be increased, but this is not preferable because the cleavage of hydroxyl groups becomes non-negligible. The hydrogen used is
The hydrogenation reaction may be carried out in a flow system or at a high pressure at normal pressure, and any reaction form such as a fixed bed suspension system may be employed for the hydrogenation reaction. Under the above-mentioned hydrogenation conditions, the double bonds in the main chain and/or side chain in polyhydroxypolybutadiene are hydrogenated, but the double bonds in the polymer used in the composition of the present invention are almost completely hydrogenated. 98% or more of the double bonds in the polymer before hydrogenation, preferably 99% or more, and more preferably until substantially no double bonds remain. It is necessary. The urethane prepolymer and curing agent to which polydimethylpolysiloxane is blended in the coating composition of the present invention are as follows. (1) Polyhydroxypolybutadiene (a) and polyol (b) in which 98% or more of the double bonds are hydrogenated as described above
and diisocyanate (c) in a ratio of equivalents (a) + (b) > (c), with a urethane prepolymer having a hydroxyl group at the terminal as the main ingredient,
To this, polyhydroxypolybutadiene (a) and/or polyol (b) with hydrogenated double bonds of 98% or more and diisocyanate (c) are added in equivalent amounts (c) > (a) and/or (b). A urethane prepolymer with terminal isocyanate groups obtained by reacting at a ratio of (2) Polyhydroxypolybutadiene (a) in which 98% or more of the double bonds are hydrogenated, polyol (b), and diisocyanate (c) are mixed in equivalents (a) + (b)>
The main ingredient is a urethane prepolymer with hydroxyl groups at the end obtained by reacting at the ratio (c), and a diisocyanate is blended as a curing agent. The aforementioned polyols are polyols exemplified by polypropylene oxide glycol, polytetramethylene oxide glycol, polyethylene-butylene adipate, polyethylene adipate, polybutylene adipate, polydiethylene adipate, acrylic polyol, 1,6-hexanediol adipate, etc. , the aforementioned diisocyanates include tolylene diisocyanate, 4.
Diisocyanates exemplified by 4'-phenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, dianisidine diisocyanate, tridene diisocyanate, dimeryl diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, etc. . The coating composition of the present invention is characterized in that polydimethylpolysiloxane is blended with the urethane prepolymer base agent and curing agent as described above. The coating composition of the present invention is particularly excellent in abrasion resistance after heat aging, abrasion resistance after weathering, and abrasion resistance in high-temperature atmospheres.It should be noted that when applied to the flocked areas of electrostatic flocking products, These performances are significantly demonstrated. If this is used in a glass run for automobiles, a product with extremely excellent performance can be obtained. The performance of the coating composition of the present invention is shown in the examples below.
It can be seen from the product test results of the comparative example that it is extremely excellent. Hereinafter, the present invention will be explained with reference to examples. However, the present invention is not limited to electrostatic flocking products shown in the following examples, but can also be applied to products of various shapes made of various materials such as rubber, plastic, metal, textiles, and ceramics. It will be obvious to those skilled in the art that it can be used as a coating composition for flocking products or other products. The details of the wear tests conducted for the following Examples and Comparative Examples are as described below. Testing machine: KI type abrasion test Test conditions: Abrasion element glass (thickness 5mm) Load 3Kg Abrasion element cycle 60 times/min Abrasion element stroke 145mm Test method: The sample was mounted on the above testing machine and electrostatic flocking was performed under the above conditions. rub the surface. In addition, various types of abrasion properties in the abrasion test are as follows. Abrasion properties after heat aging treatment After leaving the sample for friction in a hot air dryer at 80°C for 200 hours, it was attached to the above testing machine and rubbed. Abrasion properties after sunshine weather-o-meter treatment After exposing the friction sample to a weather-o-meter using two carbon arc lamps for 200 hours, it was attached to the above testing machine and rubbed. Abrasion resistance in an atmosphere of 60°C A sample before aging is attached to the above testing machine and rubbed while maintained in an atmosphere of 60°C. Example 1 (a) Polyhydroxybutadiene (molecular weight approx.
2000) 200 parts Polypropylene oxide glycol (molecular weight approximately 2000) 200 parts 4,4'-diphenylmethane diisocyanate 25 parts Dimethyl sulfoxide A mixture of 425 parts was reacted at 80°C for 3 hours in dry nitrogen gas to form a hydroxyl group at the end. A urethane prepolymer having the following was produced. (b) Dry a mixture of 100 parts of polyhydroxypolybutadiene (molecular weight approximately 2000) with hydrogenated double bonds of 98% or more, 56 parts of 4,4'-diphenylmethane diisocyanate, and 168 parts of dimethylformamide at 80°C for 3 hours. A urethane prepolymer having isocyanate groups at the terminals was produced by reacting in a gas. (c) 260 parts of (a) and 100 parts of (b) were mixed to obtain a urethane solution. (d) To 100 parts of the solution obtained in (c), add 10 parts of polydimethylpolysiloxane (100,000 cst) and 3 parts of carbon black.
A coating composition was prepared. (e) This coating composition was applied to the flocked surface of the electrostatic flocked product and dried at 80°C for 30 minutes. (f) The same operation as in (e) was performed using only the urethane polymer in (c) above to obtain a product as a comparative example (Comparative Example 1). Example 2 (a) 200 parts of polyhydroxypolybutadiene (molecular weight approximately 2000) in which 98% or more of double bonds are hydrogenated,
Polypropylene oxide glycol (molecular weight approx.
2000) 2000 parts, 25 parts of 4,4'-diphenylmethane diisocyanate, 1000 parts of dimethylformamide
The mixture was reacted at 80°C for 3 hours in dry nitrogen gas to synthesize a urethane prepolymer. 23 parts of 1,5-naphthalene diisocyanate was mixed into this urethane prepolymer as a curing agent. (b) Add Example 1(d) to 100 parts of the mixture obtained in (a) above.
Similarly, polydimethylpolysiloxane,
A coating composition was prepared by adding carbon black. (c) This coating composition was applied to an electrostatic flocked product in the same manner as in Example 1(e). (d) Using only the mixture obtained in (a) above, the operation (c) was carried out to obtain a comparative product (Comparative Example 2). The abrasion test results of the above-mentioned Example and Comparative Example products are shown in a table.

【table】
(Unit: times)
Note: In both cases, base material exposure is based on the number of times listed.

Claims (1)

[Claims] 1. Polyhydroxypolybutadiene (a) in which 98% or more of double bonds are hydrogenated, polyol (b), and diisocyanate (c) are reacted in a ratio of equivalents (a) + (b) > (c). The obtained urethane prepolymer having hydroxyl groups at the terminals is used as the main ingredient, and to this, polyhydroxypolybutadiene (a) and/or polyol (b) in which 98% or more of double bonds are hydrogenated and diisocyanate (c) are added. A urethane prepolymer or diisocyanate having an isocyanate group at the end obtained by reacting at a ratio of equivalent (c) > (a) and (or) (b) is blended as a curing agent, and polydimethylpolysiloxane is further blended. A paint composition characterized by: