JPS60180776A - Unwoven cloth for polishing - Google Patents

Abstract

PURPOSE:To increase the water repellent property of an unwoven cloth for polishing and improve polishing effect by using a specified urethane compound and making a polishing liquid effectively exist on a contact surface between this unwoven cloth and an object being polished. CONSTITUTION:An entangled fiber consisting of a synthetic fiber (e.g., polyester fiber, polyamide fiber), A is impregnated with well-balanced and/or non-balanced urethane compound (e.g., a product produced by reaction between mono-alcohole having straight chain or ramified perfluoroalkyl group having 4-20 carbon numbers, and di-isocyanate) having polyurethane elastomer and perfluoroalkyl group, to provide an unwoven cloth for polishing. In this case, the content of fluorine existing in the urethane compound is 0.02-0.2wt%, increasing a water repellent effect, and a polishing liquid is put on a contact surface between an object to be polished and the unwoven cloth for polishing, to increase the polishing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polishing nonwoven fabric for polishing silicon wafers, glass, metals, etc., and in particular, a polishing liquid containing abrasive grains is effectively present on the contact surface between the object to be polished and the polishing nonwoven fabric. This invention relates to an abrasive nonwoven fabric designed to.

Traditionally, nonwoven fabrics for abrasive use have been made by impregnating a fiber entangled body made of synthetic fibers with a solution of a polyurethane elastomer in a water-miscible organic solvent, and coagulating and desolventizing the fabric in a non-solvent whose main component is water. However, this polishing nonwoven fabric absorbs the polishing liquid and the polishing liquid may be effectively present on the contact surface between the object to be polished and the polishing nonwoven fabric, and the polishing effect was not good.

In order to improve this drawback, attempts have been made to impart water repellency to conventional polishing nonwoven fabrics. That is, the conventional polishing nonwoven fabric was impregnated with a higher fatty acid derivative or other water repellent solution or water repellent dispersion and dried to give it full water repellency, but the durability was not improved in terms of water repellency. It was lacking, it wasn't enough.

The present inventor considered adding water repellency to the polishing nonwoven fabric when manufacturing the entire polishing nonwoven fabric, instead of post-treating the polishing nonwoven fabric with a water repellent as in the past. These agents are poorly soluble or insoluble in dimethylformamide, methyl ethyl ketone, dioxane, tetrahydrofuran, acetone, etc., which are used as water-miscible organic solvents for polyurethane elastomers, and cannot be uniformly dissolved and dispersed in polyurethane elastomer solutions. However, no abrasive nonwoven fabric with sustained water repellency could be obtained. However, a low molecular weight urethane compound containing a perfluoroalkyl group is soluble in the water-miscible organic solvent solution, and moreover, it hardly interferes with coagulation and desolvation during wet coagulation of a water-temperature solution of a polyurethane elastomer in a water-miscible organic solvent. They discovered that there is no such thing and completed the present invention.

That is, the abrasive nonwoven fabric of the present invention is made by impregnating a fiber entangled body made of synthetic fibers with a polyurethane distomer and a symmetrical and/or asymmetrical urethane compound having a perfluoroalkyl group.

As the synthetic fibers, any fibers commonly used in nonwoven fabrics such as polyester fibers and polyamide fibers can be used. The tangled fibers can be either made of long fibers or short fibers, and can be used.

As the urethane compound having a perfluoroalkyl group, a reaction product of a monoalcohol and a diisocyanate having a linear or branched perfluoroalkyl group having 4 to 20 carbon atoms can be used. Monoalcohols having a linear or branched perfluoroalkyl group having 4 to 20 carbon atoms include 0F3 (OFF), OHOF, (OF2), 0HCF'
3 (CF2), 60HCF+3 (CIP2) 110HG
! F3 (OF2) 7B02N (OR 0H20H20H
OF3 (OF2), 802N (OH20H5) (!H2
0H20HOF6 (OIF2), E1O□N (OH20
H20H3)OH20H20HOF3(CF2n, 80
Examples include, but are not limited to, 2N(OH3)OF3(OF2), 0H20H20H CF5(CII12)11aH2CH20H, and the like.

In addition, as the diisocyanate, 80/2.4-tolylene diocyanate), 2.6-tolylene diocyanate), 2.4/2,6) lylene dicyanate
In addition to 20 mixtures, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, etc., the diisocyanate is added to glycols such as polytetramethylene ether glycol, polycaprolactone, polypropylene glycol, polyethylene adipate, and polybutylene adipate. A diisocyanate having inocyanate groups at both ends obtained by addition may also be used. The urethane compound having a perfluoroalkyl group has a fluorine content of 002 to 020% based on the total solid content of the polyurethane distomer and fluorine-containing urethane.
It is preferable that it is within the range of . Particularly preferably α03
When the p% of α15X is less than 0.02%, a sufficient water repellent effect cannot be obtained, and when it is more than 0.020%, the water repellent effect of the perfluoroalkyl group reaches an equilibrium state, and no effect of increasing the amount added is observed. Furthermore, in the fluorine-containing urethane compound having a perfluoroalkyl group, the monoalcohols containing perfluoroalkyl groups added to both ends may be the same compound or may be different compounds. A compound in which the two-fluoroalkyl group monoalcohols at both ends are the same is called a symmetrical compound, and a case where they are different is called an asymmetrical compound.

EXAMPLES Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Examples] Polyethylene adibe with a molecular weight of 1000 as fluorine-containing urethane) 100 f, dimethylformamide 14
8 and tolylene diinocyanate 348F are reacted to obtain a prepolymer having an incyanate group at the end, and this is reacted with perfluorooctyl alcohol B'12ff to obtain a fluorine-containing urethane compound having a fluorooctyl group at the end. A dimethylformamide solution was obtained.

2 kO Tennis 0%, 30 Denis 30% 5
A short fiber entangled body of polyethylene terephthalate with a fiber length of 1 yen (fabric weight 440j'/yj% thickness 32mm), polyethylene adipate, a polyurethane nystomer whose main components are 4,4'-diphenylmethane diincyanate, and the above-mentioned fluorine-containing urethane. were impregnated with a dimethylformamide solution containing 125% and 3% QO, respectively, coagulated in water at 20°C, desolventized, washed with water, and dried with ventilation at 130°C.
A nonwoven fabric sheet was obtained in which the ratio of (fiber) to (polyurethane di-stomer and fluorine-containing urethane) was 100 to 95. This is 1
This was introduced into a heated roll at 60° C. to obtain a nonwoven fabric having a thickness of 29τio and excellent surface smoothness, and then sliced on both sides to obtain a nonwoven fabric with a clearance of 924 m. It was very water repellent. When a silicon wafer was polished for 30 minutes with alumina-containing polishing liquid added to it, 1
3μ polishing was possible.

Comparative Example 1 A non-woven fabric of 248 was obtained in the same manner as in Example 1 except that fluorine-containing urethane was not used, but most of the polishing liquid impregnated with it was absorbed into the non-woven fabric, and the polishing effect was low and the polishing effect was low and the polishing effect was low even after 30 minutes. The amount of polishing H was 25μ, which was significantly inferior to Example 1 in terms of polishing effect.

Comparative Example 2 After obtaining 24 pieces of nonwoven fabric in the same manner as in Example 1 except that fluorine-containing urethane' (i- was not used), a water-dispersible water and oil repellent having a perfluoroalkyl base (Dickgard F-70) was prepared. (manufactured by Dainippon Ink and Chemicals Co., Ltd.) to impart water and oil repellency.Next, the silicon wafer was polished for 30 minutes with the same alumina-containing polishing liquid as in the example, but the amount of polishing was 30μ. , the polishing effect was inferior.

As is clear from the Examples and Comparative Examples, the polishing nonwoven fabric of the present invention can effectively make the polishing liquid exist on the contact surface between the object to be polished and the polishing nonwoven fabric, and the effect lasts semi-permanently. Therefore, it can be seen that the polishing effect is excellent.

patent applicant

Claims (2)

[Claims] (1) An abrasive nonwoven fabric made by impregnating a fiber entangled body made of synthetic fibers with a polyurethane di-stomer and a symmetrical and/or asymmetrical urethane compound having a hyber-fluoroalkyl group. (2) The polishing nonwoven fabric according to claim 1, wherein the fluorine content in the polyurethane elastomer and the symmetrical and/or asymmetrical urethane compound having a perfluoroalkyl group is from QO2 to 02% by weight.