阅读说明：本技术 聚氨酯抛光垫片层的制备方法 (Preparation method of polyurethane polishing pad layer ) 是由 李涛 房玉俊 孟平 宿金明 于 2020-06-30 设计创作，主要内容包括：本发明属于聚氨酯应用技术领域,具体涉及一种聚氨酯抛光垫片层的制备方法,包括以下步骤：(1)多元醇、中空聚合物微球和抗氧剂混合后制得异氰酸根质量含量为7.5-15％的预聚物；(2)通过薄膜蒸发的方法,得到游离二异氰酸酯单体含量小于0.1％的低游离预聚体；(3)将低游离预聚体组分与扩链剂组分充分混合,浇注于模具中开模、硫化制得聚氨酯抛光垫片层。本发明采用的低游离聚氨酯预聚体,具有流动性好、凝胶时间长且成型速度快的优点,可显著改进聚氨酯抛光垫片层的物理机械性能,同时通过采用低聚物类的胺类或醇类固化剂,进一步提升了产品的成型工艺,具有优良的抛光效果,今儿满足市场对高性能聚氨酯抛光垫的需求。(The invention belongs to the technical field of polyurethane application, and particularly relates to a preparation method of a polyurethane polishing gasket layer, which comprises the following steps: (1) mixing polyalcohol, hollow polymer microspheres and an antioxidant to prepare a prepolymer with the mass content of isocyanic acid radical of 7.5-15%; (2) obtaining a low-free prepolymer with the free diisocyanate monomer content of less than 0.1 percent by a film evaporation method; (3) and fully mixing the low-free prepolymer component and the chain extender component, pouring the mixture into a mold, opening the mold, and vulcanizing to obtain the polyurethane polishing gasket layer. The low-free polyurethane prepolymer adopted by the invention has the advantages of good fluidity, long gel time and high molding speed, can obviously improve the physical and mechanical properties of a polyurethane polishing pad layer, and simultaneously further improves the molding process of the product by adopting low-polymer amine or alcohol curing agents, has excellent polishing effect, and meets the market demand for high-performance polyurethane polishing pads.)

1. A preparation method of a polyurethane polishing gasket layer is characterized by comprising the following steps: the method comprises the following steps:

(1) mixing polyol, hollow polymer microspheres and an antioxidant, dehydrating until the water content is less than or equal to 0.03%, and then reacting with diisocyanate at 70-85 ℃ to obtain a prepolymer with the mass content of isocyanate of 7.5-15%;

(2) separating out unreacted free diisocyanate monomer in the prepolymer prepared by the reaction in the step (1) by a film evaporation method to obtain a low-free prepolymer with the free diisocyanate monomer content of less than 0.1%;

(3) and fully mixing the low-free prepolymer component and the chain extender component, pouring the mixture into a mold, opening the mold, and vulcanizing to obtain the polyurethane polishing gasket layer.

2. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the mass ratio of the polyol, the hollow polymer microspheres, the antioxidant and the diisocyanate in the step (1) is 30-74:0.1-0.5: 25-70.

3. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the polyol is one or more of polytetrahydrofuran ether polyol with the number average molecular weight of 250-2000 and the functionality of 2 or polycaprolactone polyol with the number average molecular weight of 1000-2000.

4. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the particle size of the hollow polymer microsphere is 10-150 μm.

5. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the antioxidant is an antioxidant 1076.

6. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the diisocyanate is one or more of 2, 4-toluene diisocyanate, 4 '-diphenylmethane diisocyanate, a mixture of 50% of 2, 4' -diphenylmethane diisocyanate and 50% of 4,4 '-diphenylmethane diisocyanate, liquefied MDI, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate or dicyclohexylmethane-4, 4' -diisocyanate.

7. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the temperature of the film during evaporation and distillation is 130-150 ℃.

8. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the chain extender is one or more than one of 4-chloro-3, 5-diaminobenzoic acid isobutyl ester, 3 '-dichloro-4, 4' -diaminodiphenylmethane, 1, 4-butanediol, hydroquinone dihydroxyethyl ether, polytetramethylene ether glycol bis (p-aminobenzoic acid) ester, 4-chloro-3, 5-diaminobenzoic acid isobutyl ester or 1, 3-propanediol-bis (4-aminobenzoic acid) ester.

9. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the mass ratio of the low-free prepolymer to the chain extender is 10: 20-35.

10. The method of making a polyurethane polishing pad layer as set forth in claim 1, wherein: the density of the polyurethane polishing pad layer is 0.75-0.95g/cm³The Shore hardness is 40-70D.

Technical Field

The invention belongs to the technical field of polyurethane application, and particularly relates to a preparation method of a polyurethane polishing gasket layer.

Background

Chemical Mechanical Polishing (CMP) is the best process technology for global planarization, and the removal of chemical reactants formed on the surface of a polished part is completed by mechanical friction, and is mainly used for processing ultra-precise surfaces (such as silicon wafers, micro integrated circuits, memories and the like) to obtain a smooth surface.

The surface lamella of the polishing pad is made of polyurethane elastomer materials at present, and considering that the lamella of the polyurethane polishing pad is mainly a polytetrahydrofuran ether elastomer which is resistant to hydrolysis and acid and alkali because of the existence of polishing liquid in the polishing process, but the lamella of the polyurethane polishing pad usually has poor performance in the aspects of wear resistance and mechanical strength. The polishing effect of CMP is due to the action of abrasive particles, which easily leave scratches and defects on the integrated circuit, and cannot meet the requirements of the current miniaturization process and strict flatness.

At present, during the production of prepolymers, there is always some free unreacted diisocyanate monomer and some polymeric products. When the low-free polyurethane prepolymer is prepared, a large amount of diisocyanate monomer is excessive (NCO/OH is more than 2), the-NCO group on the free diisocyanate monomer has high activity relative to the-NCO group on the oligomer, and the polymer polyol is easier to react with the-NCO group on the free diisocyanate monomer, so that a large amount of oligomer with a three-unit structure is generated in a prepolymer system.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the polyurethane polishing pad prepared by the method has better process operability, lower quality risk, higher mechanical property and better polishing effect, and meets the requirement of the market on the high-performance polyurethane polishing pad.

The preparation method of the polyurethane polishing gasket layer comprises the following steps:

(1) mixing polyol, hollow polymer microspheres and an antioxidant, dehydrating until the water content is less than or equal to 0.03%, and then reacting with diisocyanate at 70-85 ℃ to obtain a prepolymer with the mass content of isocyanate of 7.5-15%;

(2) separating out unreacted free diisocyanate monomer in the prepolymer prepared by the reaction in the step (1) by a film evaporation method to obtain a low-free prepolymer with the free diisocyanate monomer content of less than 0.1%;

(3) and fully mixing the low-free prepolymer component and the chain extender component, pouring the mixture into a mold, opening the mold, and vulcanizing to obtain the polyurethane polishing gasket layer.

The mass ratio of the polyol, the hollow polymer microspheres, the antioxidant and the diisocyanate in the step (1) is 30-74:0.1-0.5:0.1-0.5: 25-70.

The polyol is one or more of polytetrahydrofuran polyether polyol with the number average molecular weight of 250-2000 and the functionality of 2 or polycaprolactone polyol with the number average molecular weight of 1000-2000, and the polytetrahydrofuran polyether polyol is preferred. When the polyurethane prepolymer is synthesized, a part of polyester polyol is added into polytetrahydrofuran ether glycol, and by means of stronger crystallinity, the mechanical strength of the polishing pad layer can be effectively improved by controlling the addition amount of the polyol on the premise of not influencing the hydrolysis resistance and acid and alkali resistance of the polyurethane elastomer, so that the polishing pad has higher removal rate and planarization capability.

The particle size of the hollow polymer microsphere is 10-150 mu m, and the hollow polymer microsphere produced by Middling group Maanshan Ministry of mining materials science and technology, Inc. is preferred. The antioxidant is preferably an antioxidant 1076.

The hollow polymer microspheres and the antioxidant are added into the isocyanate raw material for preparing the prepolymer, so that the scratches can be effectively reduced, and meanwhile, the light stability and the anti-yellowing capacity of the polyurethane polishing sheet layer can be effectively improved, so that the polyurethane polishing sheet layer has excellent weather resistance and color stability, the aging of the product is delayed, and the service life and the storage life of the product are prolonged.

The diisocyanate is one or more of 2, 4-toluene diisocyanate, 4 '-diphenylmethane diisocyanate, a mixture of 50% of 2, 4' -diphenylmethane diisocyanate and 50% of 4,4 '-diphenylmethane diisocyanate, liquefied MDI, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate or dicyclohexylmethane-4, 4' -diisocyanate.

The chain extender is one or more than one of 4-chloro-3, 5-diaminobenzoic acid isobutyl ester, 3 '-dichloro-4, 4' -diaminodiphenylmethane, 1, 4-butanediol, hydroquinone dihydroxyethyl ether, polytetramethylene ether glycol bis (p-aminobenzoic acid) ester, 4-chloro-3, 5-diaminobenzoic acid isobutyl ester or 1, 3-propanediol-bis (4-aminobenzoic acid) ester.

The mass ratio of the low-free prepolymer to the chain extender is 10: 20-35.

The density of the polyurethane polishing pad layer is 0.75-0.95g/cm³The Shore hardness is 40-70D.

The invention adopts a unique molecular distillation technology combined separation process, the feeding temperature is controlled at 90 ℃, the temperature is controlled at 130-150 ℃ during distillation, the vacuum degree is controlled at 0.1mbar, the feeding rate is 600g/h, and the high-performance polyurethane prepolymer is obtained after separation by a two-stage film evaporator. Then separating free diisocyanate monomers in the system by a unique molecular distillation technology to obtain the high-performance polyurethane prepolymer with low free diisocyanate content, narrow relative molecular mass distribution and more regular molecular structure. The low-free prepolymer has good fluidity, long gel time and high forming speed, so that the demolding time is shortened, the production efficiency is improved, the forming performance and the physical and mechanical properties of the material are obviously improved, the low-free prepolymer is more suitable for the working environment with high requirements on dynamic performance such as high speed, high bearing capacity and the like, the distribution of the filler can be controlled by virtue of longer gel time when the low-free prepolymer is introduced into the preparation of a polyurethane polishing pad layer, and the polishing pad has more stable performance, longer service life and better polishing effect.

Compared with the prior art, the invention has the following beneficial effects:

1. the polyurethane polishing pad has less free TDI during synthesis of the prepolymer, and has better dynamic performance.

2. The synthesized prepolymer is a low-free prepolymer with the free diisocyanate monomer content of less than 0.1 percent, has good fluidity, long gel time and high forming speed, and ensures that the structure of the prepolymer molecules is more regularly arranged.

3. The chain extender of the curing agent of the invention is prepared from 1, 3-propylene glycol-bis (4-aminobenzoic acid) ester and 4-chloro-3, 5-diaminobenzoic acid isobutyl ester which are oligomeric diamine chain extenders in the components, and can endow the polyurethane polishing pad with good mechanical properties.

(4) The polyurethane polishing gasket layer prepared by the invention has longer service life and storage life of products, better mechanical property, higher polishing efficiency and better polishing effect, and can generate fewer scratches on the surface of a polished piece.

Detailed Description

The present invention will be further described with reference to the following examples.