JPH04115875A - Polyurethane foaming body and polishing method using the same - Google Patents

Abstract

PURPOSE:To eliminate blinding, and to enable grinding while fitting to an uneven face with a proper elastic deformation, by using for grinding a polyurethane foaming body having a specific self dressing property and characteristic hardness, elastic characteristic as well. CONSTITUTION:A polyurethane foaming body composed of the reaction product of a highpolymer polyol, chain stretching agent and polyisocyanade compound and polishing abrasive grains, including a lot of independent foams in 100-300 microns mean sectional diameter and whose density is 0.40-0.55, is taken. It has a self dressing property which wears naturally at the rate of 3-6mm/24 hours in case of polishing, and has the elastic characteristics of the hardness at 25 deg.C being 75-90, the compressibility at 50-60 deg.C being 2-3%, and compression elastic modulus being 70-80%. Plural polyurethane pads consisting of this polyurethane foaming body are equipped in series to perform grinding.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to polyurethane foam suitable for abrasive materials, particularly for polishing and finishing wire glass products with a large surface area and significant irregularities. The present invention provides a polyurethane foam suitable as a material and a method for polishing wired glass products using the same.

(Prior Art) Hard polyurethane foam has conventionally been used as a polisher for polishing glass such as optical lenses and photomasks.

This hard abrasive bat has little elastic deformation and excellent wear resistance, making it suitable as a glass abrasive material, but as the polishing time progresses, clogging occurs and the grinding power decreases. However, the common method is to use diamond pellets to seal the clogged vat surface after polishing for a certain period of time to expose a new surface.

(Problem to be solved by the invention) However, when several dozen polishing machines are installed in series and polishing is performed continuously in one motion, such as when polishing plate glass, the polishing vat must be sheathed. This makes it unsuitable because it clogs over time and reduces the amount of grinding.Also, when used as a polishing bat for mesh plate glass products with significant unevenness, it does not have the elastic deformation to adapt to the unevenness of the surface. It has the disadvantage that it is difficult to obtain area coverage.

For this reason, hard felt made of goat, cow, and other animal hair, which has been used for polishing plate glass, has been used as the polishing material for wired plate glass products, but the quality is inconsistent1, and the surface accuracy is poor. There is a demand for superior, highly productive abrasives.

In order to solve the above-mentioned problems and improve productivity, the inventors of the present invention aimed to improve the self-dressing property and hardness of the polyurethane pad and the temperature range (50 to 6
As a result of repeated studies mainly focusing on elastic deformation at 0℃),
We have succeeded in developing a polyurethane foam that has a long pot life and excellent performance in terms of grinding power and surface precision as an abrasive material for wired plate glass products, leading to the completion of the present invention.

(Means for Solving the Problems) The present invention provides: (1) An independent film with an average cross-sectional diameter of 100 to 300 microns composed of a polymer polyol, a reaction product of a chain extender and a polyisocyanate compound, and abrasive grains. A polyurethane foam containing many cells and having a density of 0.40 to 0.55, which has a density of 3 to 6 mm/2 during polishing.
It has a self-dressing property that naturally wears out at a rate of 4 hours, has a hardness of 75 to 90 at a temperature of 25°C, and a compressibility of 2 to 3% at a temperature of 50 to 60°C.
, a polyurethane foam (A) characterized by having elastic properties with a compressive modulus of 70 to 80%, and (2) a polymeric polyol, a reaction product of a chain extender and a polyisocyanate compound, and abrasive grains. A polyurethane foam having a density of 0.35 to 0.50 containing a large number of closed cells with an average cross-sectional diameter of 80 to 200 microns, and having a density of 1 to 3 mm/24 during polishing.
Has a self-dressing property that wears out naturally at a rate of time,
and has a hardness of 60 to 75 at a temperature of 25°C,
A polyurethane foam (B) characterized in that it has elastic properties of a compressibility of 3 to 5% and a compression modulus of 80 to 90% at a temperature of 50 to 60°C.

(3) a grinding step in which a plurality of polyurethane pads made of the polyurethane foam (A) described in (1) above are installed in series; A method for polishing wired sheet glass, characterized in that a polishing process using a plurality of polyurethane pads in series is performed continuously in one motion. exists in

The polyurethane foam (A) of the present invention is particularly suitable for use as a pad for grinding (coarse grinding M) the surface of a mesh glass plate with significant irregularities, and has a density of 0.40 to 0°55, and a polishing pad of 3 to 6 mm/ It is necessary to have self-dressing properties that wear out at a rate of 24 hours.

When the density is 0.55 or more, the wear of the foam during grinding of a plate glass is in the range of 1 to 2 mm/24 hours, clogging phenomenon occurs and the grinding force is reduced. On the other hand, the density is 0.
If it is less than 40, the wear of the foam increases to 7 to 10 mm/24 hours, the pot life is short, and there is a problem in economical efficiency.

The average cross-sectional diameter of the large number of closed cells contained therein is preferably 100 to 300 microns, and the thicker the walls between the cells, the greater the abrasion resistance.

Further, it is necessary that the hardness at a temperature of 25° C. is 75 to 90, and the elastic properties are such that the compressibility at a temperature of 50 to 60° C. is 2 to 3% and the compressive elastic modulus is 70 to 80%.

Even if it has such elastic properties, if the hardness is less than 75, the bat will deform and the grinding force will decrease.

On the other hand, if the hardness is 90 or more, the fit to the glass surface will be poor, and the grinding force will be reduced due to the sliding phenomenon.

Due to the specific self-dressing properties mentioned above and the polyurethane foam having both hardness and elasticity, it has a long pot life.
A polishing bat with excellent grinding power and surface precision can be obtained.

The polyurethane foam (B) of the present invention is suitable for final polishing of the netted root lath surface roughly polished by the polyurethane foam (A), and has a density of 0.35 to 0.
．． 50, and it is necessary to have a self-dressing property that wears out at a rate of 1 to 3 mm/24 hours during polishing.

When the density is 0.50 or more, the wear of the foam during grinding of plate glass is in the range of 1 mm/24 hours or less, clogging phenomenon occurs and the grinding force decreases.

On the other hand, if the density is less than 0.35, the wear of the foam will be as high as 5 to 7 mm/24 hours, the pot life will be short, and deformation will occur, resulting in poor polishing accuracy.

The average cross-sectional diameter of the large number of internal closed cells is 80 to 2
The thickness is preferably 0.00 microns, and the thinner the walls between the bubbles, the easier it is to obtain surface accuracy.

Further, it is necessary to have elastic properties such as a hardness of 60 to 75 at a temperature of 25°C, a compressibility of 3 to 5% and a compression modulus of 80 to 90% at a temperature of 50 to 60°C.

Even if it has such elastic properties, if the hardness is less than 60, the bat will deform, the grinding force will decrease, and uniform polishing will not be possible. On the other hand, if the hardness exceeds 75, scratches will occur on the glass surface, which is not preferable.

Due to the specific self-dressing properties mentioned above and the polyurethane foam having both hardness and elasticity, it has a long pot life.
A polishing bat with excellent polishing power and surface precision can be obtained.

The present invention includes a grinding process in which a plurality of polyurethane pads made of polyurethane foam (A) having a specific self-dressing property, hardness and elasticity are installed in series, and a grinding process having a specific self-dressing property, hardness and elasticity. It is essential to carry out the polishing process in which multiple polyurethane pads made of polyurethane foam (B) are connected in series in one continuous motion, and by performing this series of polishing, it is possible to achieve high surface precision. It is possible to efficiently produce wired plate glass products, and for example, if all processes are performed using a polyurethane pad made of polyurethane foam (A) alone, it has excellent grinding power, but it is difficult to obtain surface accuracy, and
If a polyurethane pad made of polyurethane foam (B) is used alone, the grinding power will be poor.

However, a polyurethane pad made of highly hard polyurethane foam (A) is equipped at the front of the grinding process.
It is okay to equip a polyurethane pad made of a material with low hardness at the rear of the grinding process.

In the present invention, the polyurethane foam (A) and the polyurethane foam (B) include a polymer polyol, a chain extender (
It is composed of a reaction product of a polyisocyanate compound (including water) and abrasive grains, and can be easily obtained with good reproducibility by regulating the amount of each component.

As the polymer polyol used in the present invention, any polyether polyol or polyester polyol can be used, but polytetramethylene glycol has excellent elasticity, and those having an average molecular weight of 400 to 800 are particularly preferred.

As the chain extender, a low-molecular compound having two or more active hydrogen atoms can be used, and water can be advantageously used since it also acts as a blowing agent.

As the polyisocyanate, various polyisocyanates having two or more functionalities can be used, and examples thereof include liquid products such as sardine cyanurate-bonded MDI and polymeric MDI.

Further, as the abrasive grains, fine particles of ordinary abrasive materials such as cerium oxide and iron oxide can be used, and the particle size thereof is arbitrary.

Note that blowing agents, foam stabilizers, reaction accelerators, etc. used in the synthesis of ordinary polyurethane foams may be used.

The mixing and foaming of these components can be carried out by uniformly mixing and foaming, and can be carried out using a conventional low-pressure foaming machine, high-pressure foaming machine, or the like.

(Operations and Effects of the Invention) In the present invention, since the polyurethane foam (A) having a specific self-dressing property and specific hardness and elastic properties is used for grinding, there is no clogging and a specific Since it can be ground while fitting into uneven surfaces through elastic deformation, the grinding force is improved by approximately 30% compared to conventional hard felt made of animal hair, resulting in high grindability and excellent surface accuracy, and a significantly longer pot life. becomes longer. Furthermore, since it is a synthetic product, the material is stable.

In addition, since polyurethane foam (B), which has a specific self-dressing property and specific hardness and elasticity properties, is used for the polishing finish, excellent surface precision with no scratches is obtained, and the pot life is significantly extended. becomes longer.

In the present invention, a grinding process using a polishing bat made of polyurethane foam (A) and a polishing process using a polishing bat made of a pinched polyurethane foam (B) are combined and carried out continuously in one motion. The drawbacks of conventional hard bats have been greatly improved.

(Example) Examples will be given below, but the present invention is not limited to these examples. In addition, "part" means "part by weight"
means.

Example 1 Polyurethane foam (A) Polytetramethylene glycol 100 parts (average molecular weight 650) Ethylene glycol 13 parts Water
0.15 parts Reaction accelerator 0.15 parts Silicone foam stabilizer 0.80 parts Cerium oxide (average particle size 1
．． 5u) 76-part modified MDI (NCO content 23%)
141 parts The ingredients on the above table were mixed uniformly using an instant mixer, and 17.0 kg of this mixture was placed in a mold (content thickness 70 mm, diameter 700 mm) preheated to 40°C.
(circular shape).

The mold was sealed and the reaction was carried out for 20 minutes. Then, after cooling the mold, the molded product was taken out and aged at 60° C. to complete the reaction, and a polyurethane foam (A) was obtained.

The surface of this foam was sliced and removed to a thickness of 60 m.
A circular polishing bat with a diameter of 680 mm was prepared.

The properties of this object are hardness 83 and density 0.47 at 25°C.
The compressibility at 50°C is 2.3%, the compressive elastic modulus is 73%, and the diameter of the internal closed cells is 100 to 2.
It is 50 microns.

The polishing side of this polishing bat has a width of 7 mm and a depth of 53 mm.
When grooves were formed vertically and horizontally at intervals of 70 mm and used to polish a mesh plate glass with large irregularities using a cerium oxide polishing liquid, the self-wear was 3 to 4 mm/
The grinding time was 24 hours, there was no clogging phenomenon, excellent grinding power was exhibited over a long period of time, and the flatness of the glass surface was also good.

Example 2 Polyurethane foam (A-2) Polytetramethylene glycol 100 parts (average molecular weight 650) Ethylene glycol 12 parts Water
0.15 parts Curing accelerator 0.30 parts Silicone foam stabilizer 0950 parts Cerium oxide
83 parts modified MI) I (NGO content 23%) 1
38 parts Each component of the above table was molded in the same manner as in Example 1 to synthesize a polyurethane foam (A-2).

Slice this foam to a thickness of 60mm and a diameter of 680m.
A circular polishing bat with a diameter of m was prepared.

The properties of this object are hardness 80 and density 0.42 at 25°C.
The compressibility at 50°C is 2.5% and the compressive modulus is 7.
5%, the internal closed cell diameter is 150 to 300
It is micron.

Grooves with a width of 7 mm and a depth of 53 mm were formed on the polishing surface side of this bat vertically and horizontally at intervals of 70 mm, and a mesh plate glass with large irregularities was polished using a cerium oxide polishing liquid. 4 to 5 mm/24 hours, shows excellent grinding power for a long time without clogging phenomenon,
The flatness of the glass surface was also good.

Example 3 Polyurethane foam (B) Polytetramethylene glycol 100 parts (average molecular weight 650) Ethylene glycol 10 parts Water
0.15 parts Curing accelerator 0.30 parts Silicone foam stabilizer 0.70 parts Cerium oxide
71 parts modified MDI (NGO content 21%) 12
0 parts Each component of the above-mentioned table was molded in the same manner as in Example 1 to obtain a polyurethane foam (B).

Slice this foam to a thickness of 60 mm and a diameter of 680 mm.
A polishing bat with a circular shape of mm was prepared.

The properties of this object are hardness 70 and density 0.40 at 25°C.
and the compressibility at 50°C is 3.0% and the compressive elastic modulus is 90
%, the internal/closed cell diameter is between 80 and 200 microns.

Grooves with a width of 7 mm and a depth of 53 mm were formed vertically and horizontally at intervals of 70 mm on the polishing surface side of this bat, and the wire plate glass that had been ground in advance in Example 1 was polished using a cerium oxide polishing liquid. , self-wear is 1 to 2 mm/
In 24 hours, there is no clogging phenomenon, excellent polishing power is exhibited over a long period of time, and an extremely flat glass surface with no scratches is obtained.

Example 4 A plurality of polishing bats having grooves made from polyurethane foam (A) according to Example 1 were used, followed by polishing bats having grooves made from polyurethane foam (A-2) according to Example 2. Following the grinding process in which a plurality of pieces were installed in series, the polyurethane foam (
When a polishing process using multiple polishing bats with grooves prepared from B) was carried out in series, the amount of polishing was significantly improved and the processing speed was faster than with conventional animal hair felt. It is faster, and because the vat does not get clogged, it can be closed for a longer time when it is ready for use, which greatly improves productivity. Furthermore, the polished product has a very smooth surface with only a few scratches.

(Note) Physical properties were measured according to the following test method.

Hardness: J l5K-6301 (JIS hardness hardness Compression rate: JTSL-1096 Compressive modulus: JISL-1096

Claims (3)

[Claims] (1) Density of 0.40 to 0.55 containing many closed cells with an average cross-sectional diameter of 100 to 300 microns composed of a polymer polyol, a reaction product of a chain extender and a polyisocyanate compound, and abrasive grains polyurethane foam of 3 to 6 mm/2 during polishing.
It has a self-dressing property that naturally wears out at a rate of 4 hours, has a hardness of 75 to 90 at a temperature of 25°C, and a compressibility of 2 to 3% at a temperature of 50 to 60°C.
, a polyurethane foam characterized by having elastic properties with a compressive modulus of 70 to 80%. (2) A density of 0.35 to 0.50 containing many closed cells with an average cross-sectional diameter of 80 to 200 microns, which are composed of a polymer polyol, a reaction product of a chain extender and a polyisocyanate compound, and abrasive grains. polyurethane foam of 1 to 3 mm/24 when polished
Has a self-dressing property that wears out naturally at a rate of time,
and has a hardness of 60 to 75 at a temperature of 25°C,
A polyurethane foam characterized by having elastic properties of a compressibility of 3 to 5% and a compression modulus of 80 to 90% at a temperature of 50 to 60°C. (3) A grinding process in which a plurality of polyurethane pads made of the polyurethane foam according to claim 1 are installed in series, and subsequently, a grinding process is performed in which a plurality of polyurethane pads made of the polyurethane foam according to claim 2 are installed. A method for polishing wired sheet glass, characterized in that a polishing process using a plurality of polishing units installed in series is performed continuously in one motion.