JPS6148413B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for shaping aromatic polyester foam.

Fibrous foams, foam cords, ropes, and foam bands made of polyolefin or polystyrene have been put into practical use.

On the other hand, as a foam made from aromatic polyester, a fibrous material with an expansion ratio of 50 times or more and low strength has been proposed in Japanese Patent Publication No. 43-3993. Use is proposed. However, no continuous product in the lower magnification range is known.

Fibrous foam can be easily made without special measures if it has an average diameter of 10 mm or less and has a circular cross-sectional shape or a slightly flattened cross-sectional shape due to the winding pressure. It is difficult to obtain a material having an approximate cross-sectional shape because even if the die shape is made into these shapes, the force during foaming causes the shape to approach a circle. This flat shape, such as a circular or rectangular approximation, can be used as a craft material such as textiles and rattan, which feature insulation or cushioning properties, and can be handled and processed to increase the covered area. This has the advantage of making it easier.

The present inventors focused on this point, and created a fibrous foam having a cross section of an approximate shape of a circle or a rectangle.
As a result of research into a method for manufacturing aromatic polyester using a simple process, the present invention was achieved.

That is, the present invention compresses an aromatic polyester fibrous foam having a diameter of 10 mm or less, which has been melt-extruded and foam-molded, with a roll before completing cooling and hardening, and forms it into a cross-sectional shape approximately of a circular or rectangular shape. This is a method for shaping an aromatic polyester foam.

The aromatic polyester used in the present invention mainly contains aromatic dicarboxylic acids (85 mol% of dicarboxylic acids).
Polyester containing a dicarboxylic acid component (accounting for the above). Representative examples of the aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, and diphenoxyethane dicarboxylic acid. . The diol components preferably used in the polyester include ethylene glycol, trimethylene glycol, tetramethylene glycol, neopentylene glycol, hexamethylene glycol, cyclohexane dimethylol, tricyclodecane dimethylol,
Examples include 2,2-bis(4·β-hydroxyethoxyphenyl)propane, 4,4'-bis(β-hydroxyethoxy)diphenylsulfone, and diethylene glycol. The polyester is p-
Oxyacids such as oxybenzoic acid (15 mol% or less based on the dicarboxylic acid component), aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, etc. are co-used in small proportions (15 mol% or less based on the dicarboxylic acid component). It may be polymerized, or a small proportion of polyfunctional compounds such as pentaerythritol, trimethylolpropane, trimellitic acid, pyromellitic acid, etc. or monofunctional compounds such as benzoic acid may be copolymerized.

Aromatic polyesters particularly preferably used in the present invention include polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,
6-naphthalene dicarboxylate, or more than 50% of the repeating units are ethylene terephthalate, butylene terephthalate or ethylene-
Mention may be made of modified polyethylene terephthalate, modified polybutylene terephthalate or modified polyethylene-2,6-naphthalene dicarboxylate consisting of 2,6-naphthalene dicarboxylate with the remainder being other components. These modified polyesters are more preferably used in which the number of other components is 30% or less of the number of repeating structural units.

Aromatic polyester foams with a diameter of 10 mm or less can be obtained by any method, but a preferred method is to obtain a foam containing 1 to 50% by weight of a substance whose boiling point is 90°C or less and a viscosity of 8000 at a temperature 15°C higher than the melting point. This is a method in which a melted aromatic polyester having a foaming ability of more than 100 mL is extruded from a die.

In order to impart foaming ability to the molten aromatic polyester, it is necessary to incorporate a gas inert to the aromatic polyester or a substance that is liquid at room temperature into the molten resin. If a substance with a boiling point of more than 90°C is used, it will tend to shrink when cooled to room temperature, so it is preferable to select a substance with a boiling point of 90°C or less.

Examples of preferable substances include carbon dioxide gas, nitrogen gas,
Inert gases such as helium, xenon, and neon, and the following organic compounds with a boiling point of 90°C or less at normal pressure, such as saturated aliphatic hydrocarbons, saturated alicyclic hydrocarbons, halogenated saturated hydrocarbons, ethers, and ketones. etc. can be mentioned. Particularly preferably used organic compounds include hydrocarbons having 7 or less carbon atoms (for example, aliphatic saturated hydrocarbons such as methane, ethane, propane, butane, hexane, etc., and alicyclic saturated hydrocarbons such as cyclohexane, methylcyclopentane, etc.). ), chlorinated saturated hydrocarbons with 2 or less carbon atoms (e.g. methyl chloride, methylene chloride, chloroform, carbon tetrachloride, ethyl chloride, dichloroethane, dichloroethylene, etc.), fluorinated saturated hydrocarbons with 2 or less carbon atoms (e.g. carbon tetrafluoride, ethyl fluoride, ethane tetrafluoride, etc.), chlorinated fluorinated hydrocarbons having 2 or less carbon atoms (e.g. chlordifluoromethane, dichlorofluoromethane, chlortrifluoromethane, dichlorodifluoromethane) , trichlorofluoromethane, dichlorotetrafluoroethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, etc.), ethers such as ethyl ether, methylal, acetaldehyde dimethyl acetal, etc., ketones such as acetone, methyl ethyl ketone, etc. Illustrated.

These may be used alone or in combination of two or more.

The proportion of an inert gas or a substance that is liquid at room temperature (hereinafter referred to as a blowing agent) added to provide foaming ability is usually 1 to 50% by weight based on the aromatic polyester. If the blowing agent is less than 1%, almost no foaming will occur, making it impossible to obtain a practical foam molded product.If the blowing agent is more than 50% by weight, the blowing agent will not be uniformly incorporated into the molten resin, resulting in gas This is not preferable because the foam may blow out, making it difficult to obtain a foam having a predetermined shape. A more preferable addition range of the blowing agent is 2 to 40% by weight.

As a method for adding a foaming agent to the molten resin, the following method can be used, for example.

a Press fit through the vent provided in the middle of the cylinder of the extruder.

b Press fit from two places: the vent part and the die part.

c Press fit into two parts using the die part.

d Press fit from 3 places: the vent part and the die part.

Further, as a method of imparting foaming ability, a method using a chemical foaming agent other than the above-mentioned method can also be used. Examples of chemical blowing agents used in this case include azodicarbonamide, p-toluenesulfonyl semicalband, 5-phenyltetrazole, a triazine compound known under the trade name Phicel THT, and a hydrazine compound known under the trade name Celogen HT550. be done.

The rolls used to compress the foam consist of a pair of upper and lower rolls, which can be spaced appropriately and at least one of which can be rotated by a drive mechanism.

The position of the roll may be any position after the foam comes out of the die and before solidification by cooling or crystallization is completed. It is preferable to determine the best position through preliminary experiments.

The foam obtained by the present invention has excellent mechanical strength, heat resistance, and chemical resistance compared to similar foams obtained from other resins, and especially in the case of polyethylene terephthalate, it has excellent heat resistance. is 150
It has sufficient performance to withstand an atmosphere of ℃.

The foam molded product obtained by the method of the present invention includes:
Stabilizers, foam nucleating agents (eg, talc), pigments, flame retardants, antistatic agents, fillers, and other additives can be included as desired.

The present invention will be explained in more detail with reference to Examples below.

Example 1 100 parts by weight of polyethylene terephthalate pellets with an intrinsic viscosity (measured at 35°C using orthochlorophenol solvent) of 0.64 were dried with hot air for 8 hours, and then 0.6 parts by weight of 1,2-diglycidylhexahydrophthalate was added to the pellets. 1 part by weight and 1.0 part by weight of talc were uniformly mixed using a U-type blender, and the pellets were sprinkled with these additives.

The pellets obtained above were put into a cylinder with a diameter of 40 mm.
mm, L/D32, extruded using an extrusion foam molding machine equipped with a die having 8 nozzles with a hole diameter of 1.5 mm,
Foam molded. In foam molding, 15% of dichlorodifluoromethane is added from the center of the molding machine cylinder.
part by weight (per 100 parts by weight of polymer) using a plunger pump, and the cylinder temperature was set at 280°C in the supply zone, 280°C in the plasticizing zone, 270°C in the metaling zone, and 270°C in the die part. The screw rotation speed was 23 revolutions, and the discharge pressure was 75 kg/cm ² . The extrudate under these conditions is placed 50cm away from the die with two rolls of 10cm diameter, consisting of an upper rubber roll and a lower metal roll, each of which can be driven separately, with a gap of 2mm.
The rotation speed was set so that the draft rate was 1.5.

After passing through the roll, it is further passed through a cooling roll to a width of 8
A flat product with a rectangular cross section of 2 mm and a thickness of 2 mm and a specific gravity of 0.35 was obtained.

Example 2 100 parts by weight of polybutylene terephthalate with an intrinsic viscosity (measured at 35°C using orthochlorophenol solvent) of 1.15 was dried with hot air at 130°C for 8 hours, and then mixed with 2 parts by weight of 5-phenyltetrazole in a V-type blender. Sprinkle it evenly with the cylinder diameter.
Extrusion foam molding was carried out using an extrusion molding machine equipped with a die of 30 m/m, L/D22 and having four nozzles with a hole diameter of 1.5 mm.

In extrusion molding, the cylinder temperature is 220℃ in the feeding zone, 240℃ in the plasticization zone, and 240℃ in the metaling zone.
The temperature was set at 240°C, the die part at 230°C, the screw rotation speed was 35 rpm, and the discharge pressure was 65 kg/cm ² .

The same roll as in Example 1 was placed 20 cm away from the die, the gap was set to 1.5 mm, and the rotation speed was set so that the draft ratio was 1.5. After passing through the rolls, the product was further passed through cooling rolls to obtain a flat product with a rectangular cross section of 6 mm in width and 1.5 mm in thickness, and a specific gravity of 0.65.

Claims (1)

[Claims] 1. A melt-extruded aromatic polyester foam with a diameter of 10 mm or less is compressed with a roll before cooling and hardening is completed, and is shaped into a cross-sectional shape approximately circular or rectangular. Method for shaping aromatic polyester foam.