JPH0546295B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to the production of synthetic resin pipes that are transparent, have good stability against solvents, and good water resistance and hot water resistance. [Prior art] Glass tubes have traditionally been used as transparent pipes because they have good heat resistance, water resistance, and hot water resistance, but they have the disadvantage of being extremely brittle, so their uses are severely limited. has been done. For example, when used in piping for the food industry, etc., it is easily destroyed by vibrations or shocks such as earthquakes, so there is a problem in using it as a piping material. On the other hand, resin pipes made from polymethyl methacrylate are also used as synthetic resin pipes. Although this resin pipe is transparent and has sufficiently improved impact resistance compared to glass pipes, it does not have sufficient heat resistance, water resistance, or hot water resistance. ) or when hot water is passed through the pipes continuously, hair cracks often occur in the pipes, so the reality is that they cannot be used as piping materials for the food industry. [Problems to be solved by the invention] The present invention has better heat resistance, water resistance, and hot water resistance than conventionally known resin pipes made from polymethyl methacrylate as a raw material, and can be sterilized by passing water vapor at high temperatures and temperatures of 100°C or higher. To provide a method for manufacturing a resin pipe that does not generate hair cracks even after treatment or when hot water is continuously flowed inside the pipe. [Means for Solving the Problems] That is, the present invention provides a polymerizable monomer composition comprising (A) 50% by weight or more of methyl methacrylate and 50% by weight or more of a monomer copolymerizable therewith; 100 parts by weight of these partial polymers and (B) a monomer having one or more allyl groups in the molecule, or 1 part of this partial polymer
~100 parts by weight is sealed in a cylindrical matrix and polymerized while rotating around the center of the matrix to produce a synthetic resin pipe. In this method, (A) is first sealed in the cylindrical matrix. , a synthetic resin pipe characterized in that it is polymerized to a semi-solid state while rotating at an arbitrary speed as the center axis of the matrix, then (B) is added and polymerized to a solid state while continuing to rotate. It is a manufacturing method. (A) A polymerizable monomer composition consisting of 50 parts by weight or more of methyl methacrylate and 50% by weight or less of a monomer copolymerizable therewith, or a partial polymer thereof (hereinafter referred to as A monomer) that can be used in the present invention. (abbreviated as body) include the following. Examples of monomers copolymerizable with methyl methacrylate include butyl methacrylate, ethyl methacrylate, ethyl acrylate, butyl acrylate, acrylic acid, methacrylic acid, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, styrene, and α-methylstyrene. etc. If the amount of methyl methacrylate is less than 50% by weight, it is difficult to obtain a transparent resin pipe, which is a feature of the present invention. Therefore, it is within the range that does not impair transparency.
Monomers copolymerizable with methyl methacrylate can be used in amounts less than 50% by weight. Next, monomers having one or more allyl groups in the molecule (hereinafter referred to as monomer B) include allyl methacrylate, 2-methylallyl methacrylate, 1-methylallyl methacrylate, allyl acrylate, 2-methylallyl methacrylate, Methylallyl acrylate, 1
- Methylallyl acrylate, ethylene glycol bisallyl carbonate, diethylene glycol bisallyl carbonate, triethylene glycol bisallyl carbonate, polypropylene glycol bisallyl carbonate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl cyanurate, and the like.
The B monomer can be used in an amount of 1 to 100 parts by weight per 100 parts by weight of the A monomer. If the B monomer is less than 1 part by weight, it is difficult to obtain a pipe with good hot water resistance, which is a feature of the present invention. However, even if B monomer is used in excess of 100 parts by weight, it is not very effective in improving hot water resistance;
Since the monomer is more expensive than monomer A, it is not preferable in terms of economy. As the polymerization initiator that can be used for monomer A and monomer B, commonly known radical polymerization initiators can be used. Preferred polymerization initiators include G-tertiary
-butyl oxide, tertiary-butyl bar-acetate, benzoyl peroxide, di-isopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, azobisisobutyronitrile, dicumyl peroxide, tertiary
-butyl hydroperoxide, methyl ethyl ketone peroxide, cumene hydroperoxide, di-tertiary-butyl diperphthalate, etc., and 0.1 to 5.0 parts per 100 parts by weight of each of monomer A and monomer B. Parts by weight of polymerization initiator can be used. Any amount of the polymerization initiator can be used depending on the desired polymerization rate and polymerization temperature. Monomer A, monomer B, and the polymerization initiator can be used as they are, but in some cases, they may be partially polymerized. In this case, it is preferable to use the composition before it loses fluidity, and in this case, the viscosity of the composition used is 100 poise or less. The cylindrical matrix may be made of any cylindrical material such as glass, metal, or plastic. It is preferable to use a material that does not easily break due to impact during rotation. Any size matrix can be used, and it is usually preferable to have a diameter of 1.0 cm to 500 cm. After enclosing monomer A and a polymerization initiator in this cylindrical matrix, the inside of the matrix is replaced with nitrogen and rotated about the center of the matrix at room temperature or a temperature of 100° C. or less. When the polymerization of the A monomer starts and it becomes a gel state, the B monomer and a polymerization initiator are added, and the mixture is polymerized to a solid state while being continuously rotated to obtain a synthetic resin pipe. In this case, after adding B monomer,
The temperature may be increased or the rotation speed may be changed. Generally, it is preferable to use a temperature that is about 50°C higher than 20°C than the temperature at which the A monomer is brought into a semi-solid state. In addition, when making the outer surface of a synthetic resin pipe also have good hot water resistance, B
The above is repeated after prepolymerization using monomers. In this case, an outer surface thickness of 10 microns or less has little effect on improving hot water resistance, and a thickness of 1000 microns or more is unnecessary for the purpose of improving only hot water resistance, and is preferred rather than economically. do not have. [Example] The present invention will be explained below with reference to Examples. Example 1 300 g of methyl methacrylate and 0.6 g of benzoyl peroxide were injected into a steel cylinder with an inner diameter of 50 mm and a length of 300 mm. After the air inside the cylinder was replaced with nitrogen gas, the cylinder was placed in hot water at 60°C. 2 at a speed of 300 revolutions per minute with the center of the cylinder as the axis
Rotated time. Methyl methacrylate adhered to the inner surface of the cylinder, making it semi-solid. Diethylene glycol bisallyl carbonate 15 to this
After adding g and 0.6 g of benzoyl peroxide and purging with nitrogen gas again, the cylinder was immersed in hot water at 95° C. and subsequently rotated at a speed of 300 revolutions per minute for 22 hours. After that, the cylindrical part was opened and the outer diameter was 50 mm.
A resin pipe with an inner diameter of approximately 36 mm and a length of 300 mm was obtained. Example 2 Methyl methacrylate 200 as monomer A component
g, 0.4 g of benzoyl peroxide, 100 g of diethylene glycol bisallyl carbonate and 4 g of benzoyl peroxide were used as the monomer B component under the same conditions as in Example 1, outer diameter 50 mm, inner diameter approximately 37 mm, length 300 mm. obtained a resin pipe. Example 3 Methyl methacrylate 150 as monomer A component
g, diethylene glycol bisallyl carbonate with 0.3 g of benzoyl peroxide as monomer B component
Under the same conditions as Example 1 except that 135 g and 5.4 g of benzoyl peroxide were used, an outer diameter of 50 mm and an inner diameter of approx.
A resin pipe with a length of 38 mm and a length of 300 mm was obtained. Example 4 20 kg of methyl methacrylate and 40 g of azobisisobutyronitrile were injected into a steel cylinder with an inner diameter of 50 cm and a length of 200 cm. After replacing the air inside the cylinder with nitrogen gas, the cylinder was heated to 60°C. The cylinder was immersed in warm water and rotated around the center of the cylinder at a speed of 100 revolutions per minute for 2 hours. Methyl methacrylate adhered to the inner surface of the cylinder, making it semi-solid. Add to this 1800g of diethylene glycol bisallyl carbonate and 200g of triallyl cyanurate.
and diisopropyl peroxydicarbonate 80g
After adding nitrogen gas and purging with nitrogen gas again, the cylinder was heated to 95
It was immersed in warm water at ℃ and then rotated at a speed of 100 revolutions per minute for 22 hours. Thereafter, the cylindrical product was opened to obtain a resin pipe with an outer diameter of 50 cm, an inner diameter of about 49 cm, and a length of 200 cm. Example 5 Methyl methacrylate 160 as monomer A component
g, 40 g of styrene and 0.4 g of benzoyl peroxide,
The same conditions as in Example 1 were used except that 20 g of diethylene glycol bisallyl carbonate and 0.8 g of diisopropyl peroxydicarbonate were used as the monomer B component, with an outer diameter of 50 mm, an inner diameter of about 38 mm,
A resin pipe with a length of 300mm was obtained. Example 6 Methyl methacrylate 120 as monomer A component
g, 20 g of acrylic acid, 60 g of styrene, and 0.4 g of benzoyl peroxide were prepared under the same conditions as in Example 1, except that 20 g of diethylene glycol bisallyl carbonate and 0.8 g of diisopropyl peroxydicarbonate were used as the monomer B component. Diameter 50
A resin pipe with an inner diameter of about 38 mm and a length of 300 mm was obtained. Example 7 Diethylene glycol bisallyl carbonate
60g and diisopropyl peroxydicarbonate
Pour 2.4 g into a steel cylinder with an inner diameter of 50 mm and a length of 300 mm. After replacing the air inside the cylinder with nitrogen gas, immerse the cylinder in warm water at 95°C and pour it into the center of the cylinder. The shaft was rotated at a speed of 300 revolutions per minute for 2 hours. Diethylene glycol bisallyl carbonate was attached to the inner surface of the cylinder, making it semi-solid. Add 300 methyl methacrylate to this
g and benzoyl peroxide, 0.6 g of benzoyl peroxide were added, the atmosphere was replaced with nitrogen gas, and the cylinder was immersed in warm water at 70℃ for 1 minute.
It was rotated for 2 hours at a speed of 300 rpm. Then 30g diethylene glycol bisallyl carbonate 1.2g diisopropyl peroxydicarbonate
and soak the cylinder in warm water at 95℃ for 1 minute.
Polymerization was continued for a further 20 hours at a speed of 300 revolutions. After that, the cylindrical item was opened, and the outer diameter was 50 mm, the inner diameter was 37 mm, and the length was 30 mm.
mm resin pipe was obtained. The outer layer of the resin pipe was made of a polymer made of diethylene glycol bisallyl carbonate with a thickness of 0.1 mm. Comparative Example 1 300 g of methyl methacrylate and 0.6 g of benzoyl peroxide were injected into a steel cylinder with an inner diameter of 50 mm and a length of 300 mm. After replacing the air inside the cylinder with nitrogen gas, the cylinder was soaked in hot water at 60°C. 2 at a speed of 300 revolutions per minute with the center of the cylindrical object as the axis.
Rotated time. Thereafter, it was further submerged in warm water at 95°C and rotated at a speed of 300 revolutions per minute for 22 hours. Unpack the cylindrical item, outer diameter 50mm, inner diameter approximately 38mm.
A resin pipe with a length of 300 mm was obtained. Comparative Example 2 Methyl methacrylate 300 as monomer A component
g and benzoyl peroxide 0.6 g, and under the same conditions as Example 1 except that 2 g of diethylene glycol bisallyl carbonate and 0.08 g of benzoyl peroxide were used as the monomer B component, an outer diameter of 50 mm and an inner diameter of
A resin pipe of 38 mm and approximately 300 mm in length was obtained. The physical properties of the resin pipes obtained in Examples and Comparative Examples were evaluated by the following evaluation tests. The results are shown in the table. (1) High-temperature steam resistance Steam at 2 atm (120°C) was blown onto the inside of each pipe for 60 seconds, and changes in the inner surface of the pipe were visually judged. ◎: No change △: Slight cracks on the inner surface ×: Large cracks on the inner surface (2) Hot water resistance 95℃ hot water was circulated inside each pipe for 5 hours, and changes in the inner surface of the pipe were observed with the naked eye. Judgment was made by ◎: No change △: Slight cracks on the inner surface ×: Large cracks on the inner surface

〔Effect of the invention〕

The synthetic resin tubular body according to the present invention has better heat resistance, water resistance, and hot water resistance than conventional resin pipes made from polymethyl methacrylate, and can be sterilized by passing through high-temperature (100°C or higher) steam. It does not cause hair cracks even when heated or hot water is continuously flowed inside the pipe, and it can withstand use as a pipe material.It has significantly better impact resistance than glass pipes, and has been known in the past. It has almost the same impact resistance as polymethyl methacrylate resin pipes, so there are no safety issues when using it as a piping material.

Claims (1)

[Claims] 1 (A) A polymerizable monomer composition consisting of 50% by weight or more of methyl methacrylate and 0 to 50% by weight of a monomer copolymerizable therewith, or a partial polymer of these 100%
parts by weight and (B) a monomer having one or more allyl groups in the molecule, or 1 to 100 parts by weight of this partial polymer are enclosed in a cylindrical matrix, and rotated around the center of the matrix. In this method, (A) is first sealed in a cylindrical matrix, polymerized to a semi-solid state while rotating at a desired speed around the center of the matrix, and then A method for producing a synthetic resin pipe, which is characterized by adding (B) and polymerizing it to a solid state while continuing to rotate it.