JP2003291155A - Manufacturing method for resin plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a resin plate containing no air bubbles with good productivity. <P>SOLUTION: In the method for manufacturing the resin plate by injecting a polymerizable raw material in a casting mold and heating the casting mold to polymerize and cure the polymerizable raw material, the casting mold is heated at the temperature T<SB>0</SB>°C in the temperature range of 30-50°C to set the polymerization ratio of the polymerizable raw material to 5 mass % or more and subsequently heated at a temperature of (T<SB>0</SB>-2)°C or lower. The polymerizable raw material to be injected is in a syrup-like state and heated at the temperature T<SB>0</SB>°C to set the polymerization ratio of the polymerizable raw material to 15 mass% or more, and the casting mold is next heated at a temperature of (T<SB>0</SB>-2)°C or lower. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a resin plate.

[0002]

2. Description of the Related Art As a method for producing a resin plate such as an acrylic resin plate, a polymerizable raw material is poured into a mold, and the mold is heated at a constant temperature so that the polymerization rate of the polymerizable raw material is 80 to 80%. A method is widely used in which the resin plate is obtained by increasing the content to 90% by mass and then polymerizing and curing the polymerizable raw material at a higher temperature.

[0003]

However, in the manufacturing method thereof, there are cases in which the polymerization rapidly progresses at the peak of the polymerization reaction of the polymerizable raw material and bubbles are mixed into the resin plate. Therefore, in order to prevent the inclusion of air bubbles, it is necessary to lower the peak temperature of the polymerization reaction, and the addition amount of the polymerization initiator has been reduced or the polymerization temperature has been lowered. However, in these polymerization methods,
There has been a problem that it takes a long time to polymerize and cure the polymerizable raw material and productivity is deteriorated.

An object of the present invention is to provide a method for producing a resin plate free from air bubbles with high productivity.

[0005]

Means for Solving the Problems The gist of the present invention is to inject a polymerizable raw material into a mold and heat the mold to polymerize and cure the polymerizable raw material. Temperature T ₀ ℃ in the temperature range of 30 to 50 ℃
The method for producing a resin plate is characterized in that the polymerization rate of the polymerizable raw material is set to 5% by mass or more by heating at 1, and then the mold is heated at a temperature of (T ₀ −2) ° C. or less.

When the polymerizable raw material to be injected has a syrup shape, it is heated at a temperature of T ₀ ° C. to increase the polymerization rate of the polymerizable raw material to 15
It is preferable to set the content to be at least mass% and then heat the mold at a temperature of (T ₀ -2) ° C or lower.

The obtained resin plate preferably has a thickness of 60 mm or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Examples of the mold used in the manufacturing method of the present invention include a mold in which two plates are laminated via a gasket. Examples of the plate include a glass plate, a tempered glass plate, and a stainless plate whose surface is polished. Examples of the gasket include vinyl chloride resin gaskets. Examples of the shape of the gasket include a hollow circular shape, a square shape, a round shape, a trapezoidal shape, and the like. The thickness and length are not particularly limited, and can be appropriately changed depending on the thickness and area of the resin plate to be manufactured.

The polymerizable raw material to be injected into the mold preferably contains 70% by mass or more of methyl methacrylate (hereinafter appropriately referred to as "MMA"). Other polymerizable raw materials include acrylic acid esters such as methyl acrylate and ethyl acrylate, methacrylic acid esters other than MMA such as ethyl methacrylate, and methacrylic acid. The polymerizable raw material may be a syrup-shaped polymerizable raw material composed of a polymer such as MMA and MMA. When the polymerizable raw material is in the form of syrup, its polymerization rate needs to be 10% by mass or less.

In order to polymerize the polymerizable raw material, 2,2'-azobisisobutyronitrile, 2,
2'-azobis (2,4-dimethylvaleronitrile),
Azo-based polymerization initiators such as 2,2′-azobis (4-methoxy2,4-dimethylvaleronitrile) and 1,1′-azobis (cyclohexane-1-carbonitrile), lauroyl peroxide, methyl ethyl ketone peroxide, It is preferable to add a peroxide type polymerization initiator such as diisopropyl peroxydicarbonate or dicyclohexane peroxydicarbonate.

Further, in the method for producing a resin plate of the present invention, various known additives such as an ultraviolet absorber, an antioxidant and a release agent may be contained in the polymerizable raw material, if necessary. it can.

In order to polymerize and cure the polymerizable raw material, 30 to 30
The mold is heated at 50 ° C., preferably at a temperature T ₀ ° C. within the temperature range of 35 ° C. to 45 ° C. to polymerize and cure. Hot water, hot air, or the like can be used to heat the mold. The smaller the variation range of T _0, the better.

When the polymerization rate of the polymerizable raw material reaches 5% by mass or more, the mold heating temperature is changed from the previous heating temperature T ₀ to 2 ° C.
The temperature is changed to a lower temperature, that is, (T ₀ −2) ° C. or lower.
The polymerization temperature is preferably changed when the polymerization rate of the polymerizable raw material is 30% by mass or less, and more preferably 25% by mass or less.

When the polymerizable raw material is in the form of syrup, when the polymerization rate of the polymerizable raw material reaches 15% by mass or more, the heating temperature of the mold is lower than the previous heating temperature T ₀ by 2 ° C. or more,
That is, it is preferable to change the temperature to (T ₀ −2) ° C. or lower.
The polymerization temperature is preferably changed when the polymerization rate of the polymerizable raw material is 40% by mass or less, and more preferably 35% by mass or less.

The heating temperature can be changed by putting the molds in different heating tanks. Also, the temperature of the heating tank can be changed. In that case, it is preferable that the change of the temperature of the heating tank is completed within 5 hours.

The heating temperature can be changed a plurality of times.

For example, the resin plate obtained has a thickness of 85 mm.
In the above case, it is preferable that the change is performed twice or more.

The polymerization time is such that the thickness of the resin plate obtained is 8
When it is less than 0 mm, it is preferably 120 to 270 hours, and when it is 80 mm or more and less than 90 mm, it is 150 to 3 hours.
20 hours is preferable, and when it is 90 mm or more,
It is preferably 200 to 420 hours.

The method for measuring the polymerization rate of the polymerizable raw material includes the following methods.

During the polymerization and curing, the mold is taken out and immersed in ice water to stop the polymerization and curing. Next, the template is decomposed, the polymerizable raw material during polymerization and curing is taken out, put in a solvent such as normal hexane, and the polymer insoluble in the solvent and the monomer soluble in the solvent are filtered with a filter paper. After the separation, the polymer on the filter paper is dried and the solvent is removed to take out only the polymer, and the mass of the polymerization intermediate is M, and the mass of the separated polymer is a. The rate X can be calculated from a / M × 100 (mass%).

After this polymerization, 100 ° C. in a hot air oven.
It is preferable to further polymerize in the temperature range of 140 ° C to 140 ° C, preferably 120 ° C to 135 ° C. The polymerization time is preferably 1 hour or more.

After the polymerizable raw material is polymerized and cured, the plate polymer can be peeled from the mold to take out the resin plate.

The thickness of the resin plate is preferably 60 mm or more.

This method is suitable for producing a resin plate free from air bubbles with high productivity.

[0025]

[Examples] (1) Method for measuring polymerization rate A mold was taken out during polymerization and curing and immersed in ice water to stop the polymerization and curing. Then, decompose the mold, take out the polymerizable raw material during polymerization and curing, put it in normal hexane,
The polymer insoluble in the solvent and the monomer soluble in the solvent are separated by filtering with a filter paper, then the polymer on the filter paper is dried and the solvent is removed to take out only the polymer, and the polymerization intermediate The polymerization rate X was calculated from a / M × 100 (mass%) by setting the mass of the body as M and the mass of the separated polymer as a.

[Example 1] A size of 1200 mm x 120 via a hollow circular vinyl chloride endless gasket having a length of 4400 mm, an outer diameter of 100 mm and a wall thickness of 10 mm.
Two 0 mm x 10 mm tempered glass plates were laminated to form a mold. Another set of molds of the same size was formed.

Next, with respect to 100 parts by mass of methyl methacrylate, 0.003 parts by mass of bis (4-t-butylcyclohexyl) peroxydicarbonate as a polymerization initiator and Aerosol OT (manufactured by American Cyanamide) as a releasing agent. 0.02 parts by mass was added and uniformly stirred to obtain a polymerizable raw material.

The polymerizable raw material 8 was placed in each of the two sets of molds.
3 kg was injected. Polymerization was carried out for 60 hours in a 40 ° C. water bath at the initial stage of polymerization. When one set of molds was taken out and the polymerization rate of the polymerizable raw material was measured, it was 13% by mass.
Another set of molds was to heat the water bath temperature to 35 ° C in 1.5 hours.
The temperature was lowered to and polymerization was carried out at that temperature for 150 hours. Then, after polymerization in an air bath at 70 ° C. for 5 hours, 5
The temperature was raised to 130 ° C. for 3 hours and then the polymerization was carried out at 130 ° C. for 3 hours to separate the plate-like polymer from the mold, and the plate thickness was about 70 m.
m acrylic resin plate was obtained. There were no bubbles in this resin plate, and the time required for polymerization was 224.5 hours.

Comparative Example 1 Using one set of molds, 40 ° C.
In a water bath for 211.5 hours, and then in an air bath for 5 hours at 70 ° C. and then in 5 hours for 13 hours.
An acrylic resin plate having a plate thickness of about 70 mm was obtained under the same conditions as in Example 1 except that the temperature was raised to 0 ° C. and then the polymerization was carried out at 130 ° C. for 3 hours. When the resin plate was moved from the water bath to the air bath, bubbles were already mixed in.

[Comparative Example 2] Using one set of templates, 0.0012 parts by mass of bis (4-t-butylcyclohexyl) peroxydicarbonate was added as a polymerization initiator.
Polymerization in a water bath at ℃ for 211.5 hours, then in an air bath at 70 ℃ for 5 hours, followed by 13 hours in 5 hours.
An acrylic resin plate having a plate thickness of about 70 mm was obtained under the same conditions as in Example 1 except that the temperature was raised to 0 ° C. and then the polymerization was carried out at 130 ° C. for 3 hours. Although air bubbles were not mixed in the resin plate when the resin plate was moved from the water bath to the air bath, air bubbles were mixed in the obtained resin plate.

[0031]

According to the manufacturing method of the present invention, a resin plate free from bubbles can be manufactured with high productivity.

Continued front page    F-term (reference) 4F071 AA33 AA80 BA03 BB12 BC05                       BC12                 4F204 AA21 AB04 AG02 AR06 EA03                       EA04 EB01 EF01 EK14                 4J011 AA03 AA05 AB02 AB03 AB15                       AC03 BB01 DB12 GA05 GB03

Claims (3)

[Claims] 1. A method for producing a resin plate in which a polymerizable raw material is injected into a mold, and the mold is heated to polymerize and cure the polymerizable raw material, wherein the mold has a temperature within a range of 30 to 50 ° C. A method for producing a resin plate, which comprises heating at T ₀ ° C to make the polymerization rate of the polymerizable raw material 5% by mass or more, and then heating the mold at a temperature of (T ₀ -2) ° C or less. 2. The polymerizable raw material to be injected is in the form of syrup, and is heated at a temperature of T ₀ ° C. to make the polymerization rate of the polymerizable raw material 15% by mass or more, and then the temperature of the template is (T ₀ −2) ° C. or less. The manufacturing method according to claim 1, wherein the heating is performed by. 3. The manufacturing method according to claim 1, wherein a resin plate having a thickness of 60 mm or more is manufactured.