JPS6025527B2 - Method for producing polyester pulp particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to polyester pulp particles having excellent heat resistance and mechanical properties, and a method for producing the same.

It is well known that fully aromatic polymers such as polyamide and polyhydrazide provide pulp particles with excellent heat resistance and mechanical properties. However, since these polymers themselves cannot be in a stable molten state, solution molding is the only way to obtain molded products.

Moreover, the solvent is limited to strong acids such as sulfuric acid and hydrofluoric acid, which are hazardous to work with, or organic polar solvents containing inorganic salts such as calcium chloride and lithium chloride as solubilizing agents. In the latter case, in particular, a large amount of inorganic salt remains in the molded product, which may reduce the characteristics, heat resistance life, and electrical properties of the final product. Furthermore, since these polymers have relatively high hygroscopicity, various problems arise when they are used in heat-resistant insulating materials and the like. The present inventors have arrived at the present invention as a result of repeated research on pulp particles that are free from such drawbacks and have excellent heat resistance and mechanical properties, and a method for producing the same.

That is, the present invention involves melt-molding a wholly aromatic polyester that has the property of forming a heterotropic melt to form a molded product having molecular orientation, and applying a scale-cutting force to the molded product to crush it into fipril shapes. This is a method for producing polyester particles characterized by the following. The molded article having molecular orientation according to the present invention need only have a structure in which molecules are oriented inside, and macroscopically, it can be in the form of a lump, granule, powder, sheet, film, film, or string. , can take various forms such as filamentous.

In the present invention, a wholly aromatic polyester having the property of forming a heterotropic melt is defined as a polyester in a molten state with 9
A polyester that has the property of transmitting polarized light in an optical system equipped with polarizers crossed at 0o, and is a polyester in which all residues substantially constituting a polymer chain are aromatic residues.

Such polyesters include, for example, 1 terephthalic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid. acids, such as symmetrical aromatic dicarboxylic acids, methylterephthalic acid, methoxyterephthalic acid, etc.

Luterephthalic acid, Bromoterephthalic acid, Diphenyl ether-2,2'-dimethyl-4,4'-dicarboxylic acid,
The main brewing ingredient is a lower alkyl, lower alkoxy or halogen substituted product of the symmetrical aromatic dicarboxylic acid such as diphenoxyethane-2,2-dichloro-4,4'-dicarboxylic acid and cyclohexane-1-methyl-1,4-dicarboxylic acid. , hydroquinone, 4,4'-dioxydiphenyl, 4,4'-dioxydiphenyl ether, 2,
Symmetrical dioxyaromatic compounds such as 6-dioxynaphthalene, 2,7-dioxynaphthalene, 4,4'-dioxydiphenoxethane, chlorhydroquinone, fromhydroquinone, methylhydroquinone, ethylhydroquinone, 2 , 2'-dimethyl-4,4-dioxydiphenyl, 3,3-dimethoxy-4,4'-dioxydiphenyl ether, 12,2'-dichloro-4,4'-dioxydiphenoxychetane. Homopolyester or copolyester (hereinafter referred to as copolyester A) whose main diol component is a lower alkyl, lower alkoxy or halogen substituted product of a dioxyaromatic compound 2p
-oxybenzoic acid, 4-oxydiphenyl-4'-carboxylic acid, 3-chloro-4-oxybenzoic acid, 3-nathoxy-4-oxybenzoic acid, 2-methyl-4-oxybenzoic acid, 2-chloro-4- Examples include copolyesters (hereinafter referred to as copolyester B) containing aromatic oxycarboxylic acids such as oxydiphenyl-4'-carboxylic acid, or lower alkyl, lower alkoxy or halogen-substituted products thereof as copolymer components. In addition to the above-mentioned aromatic dicarboxylic acids, acid components that can be used in the production of copolyesters A and B include isophthalic acid, diphenyl ether-3,3-dicarboxylic acid, and diphenyl-3
, 4'-dicarboxylic acid, diphenoxychetane-3,3-
dicarboxylic acid, naphthalene-1,6-dicarboxylic acid, m
-oxybenzoic acid, cyclohexane-1,3-dicarboxylic acid, 5-methylisophthalic acid, 5-chloroisophthalic acid, 4-methylisophthalic acid, 5-tertiary butylisophthalic acid, diphenyl ether-4,4'-dichloro-1 3
, 3'-dicarboxylic acid, diphenyl-3,4'-dimethyl-4,3'-dicarboxylic acid, diphenoxyethane-
Aromatic dicarboxylic acids such as 2,2-dibromo-3,3-dicarboxylic acid, naphthalene-2,7-dichloro-1,6-dicarboxylic acid, 4-ethoxy-3-oxybenzoic acid, aromatic oxycarboxylic acids, or lower alkyls thereof Alternatively, halogen substituted products and carbonic acid can be mentioned.

In addition to the above-mentioned dioxyaromatic compounds, diol components that can be used in the production of copolyesters A and B include resorcinol, 3,3'-dioxydiphenyl, 3,3
'-dioxydiphenyl ether, 1,6-dioxynaphthalene, 3,3'-dioxydiphenoxyethane,
4-chlorresorcin, 4-ethoxyresorcin, 4
-Bromresorcin, 4,4'-dimethoxy-3, godioxydiphenyl, 4,4'-dimethyl-3,3'
-dioxydiphenyl, 4,4'-dimethoxy-3,
3'-dioxydiphenyl ether, 2,4'-diphenyl ether.

-3,3'-dioxydiphenyl ether, 2,5-
Examples include aromatic dioxy compounds such as dichloro-1,6-dioxynaphthalene, 2,2'-dibromo-3,3-dioxydiphenoxyethane, and lower alkyl, lower alkoxy, or halogen-substituted products thereof. Preferred polyesters of the present invention include, for example, lp-oxybenzoic acid and terephthalic acid, isophthalic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylefur-4,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, One or more aromatic dicarboxylic acids or alicyclic dicarboxylic acids selected from the group consisting of dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, and hydroquinone, chlorohydroquinone, methylhydroquinone, 4,4'-dicarboxylic acid. Copolyester consisting of one or more dioxy aromatic compounds selected from the group consisting of oxydiphenyl and 4,4'-dioxydiphenyl ether 2 Terephthalic acid, diphenyl ether-4,4'-dicarvone Aromatic dicarboxylic acid selected from the group consisting of diphenyl-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, and naphthalene-2,7-dicarboxylic acid. and/or one or more alicyclic dicarboxylic acids and hydroquinone, chlorohydroquinone, methylhydroquinone, 4,4'-
Homopolyester or copolyester consisting of one or more dioxyaromatic compounds selected from the group consisting of dioxydiphenyl and 4,4'-dioxydiphenyl ether 3 Terephthalic acid, diphenyl-4,4'-dicarboxylic acid , diphenoxyethane-4,4'-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, and one or more aromatic dicarboxylic acids selected from the group consisting of carbonic acid and hydroquinone, chlorohydroquinone, methylhydroquinone,
It is a copolyester consisting of one or more dioxy aromatic compounds selected from the group consisting of 4,4'-dioxydiphenyl and 4,4'-dioxydiphenyl ether.

A particularly preferred polyester of the present invention is l
Copolyester of p-oxybenzoic acid, isophthalic acid and/or terephthalic acid and hydroquinone and/or 4,4-dioxydiphenyl 2 p-oxybenzoic acid, diphenoxyethane-4,4'-dicarboxylic acid and hydroquinone and or copolyester with chlorohydroquinone, p-oxybenzoic acid, cyclohexane-1,4-
Copolyester of dicarboxylic acid and hydroquinone and/or chlorohydroquinone 4 Copolyester of p-oxybenzoic acid, isophthalic acid, carbonic acid and hydroquinone 5 Copolyester of terephthalic acid, diphenoxyethane-4,4-dicarboxylic acid and chlorohydroquinone Polyester 6 Copolyester of terephthalic acid, naphthalene-2,6-dicarboxylic acid and methylhydroquinone 7 Copolyester of terephthalic acid, carbonic acid and hydroquinone, etc.

The polyester of the present invention can be produced by a conventional method.

For example, 1. An aromatic dicarboxylic acid and a lower fatty acid ester of a dioxyaromatic compound, such as acetic acid, are polymerized by heating together with a lower fatty acid ester of an aromatic oxycarboxylic acid, such as acetic acid, according to the specifications. 2. An aromatic dicarboxylic acid, such as phenol 3. The aromatic dicarboxylic acid and the dioxyaromatic compound are polymerized by heating, if necessary, with the aryl ester of an aromatic oxycarboxylic acid, such as phenol.3. The reaction mixture is reacted with a diaryl carbonate such as diphenyl carbonate together with a carboxylic acid, and the reaction mixture is then thermally polymerized. There are methods such as polymerization in the presence or absence of a hydrochloric acid agent.

In this polymerization, inert compounds with high boiling points such as diphenyl, diphenyl ether, diphenooxybenzene, terphenyl, alkylnaphthalenes such as methylnaphthalene and ethylnaphthalene, and partially hydrogenated products of terphenyl are coexisted in the reaction system as necessary. can be done.

The present inventors have demonstrated that polyesters with the property of forming anisotropic melts are more rigid than general polymers that do not form anisotropic melts, and that they are more rigid than general polymers that do not form anisotropic melts, and are In the lying state, scales can be oriented with a smaller external force than polymers with general flexible chains, and once oriented, the orientation is extremely relaxed, and it is easy to create a higher-order structure like this. The present inventors have discovered that a region with low molecular fiber density and weak lateral bonding force is formed along the length of the fiber, and that when a moderate cutting force is applied to this region, fiprillization is extremely easy.The present invention has been achieved based on this discovery.

The molded product having molecular orientation referred to in the present invention is of course not limited to a molded product obtained from an optically anisotropic melt or solution, and the polymer itself essentially forms an anisotropic melt. It may be formed from an isomergic melt or solution as long as it has the properties to do so.

Even in the latter case, molded products with molecular orientation can be prepared more easily than with general polymers with flexible chains, but in optically anisotropic melts or solutions, there is already considerable molecular orientation in those states. Molded products obtained from these materials can be particularly preferably used in the present invention. In order to obtain molded products with molecular orientation, these melts may be introduced into an aqueous precipitation tank and precipitated as fine particles under an appropriate shearing force, or they may be formed into lumps through a nozzle, slit, etc. It may be extruded into a gas or liquid coagulation atmosphere in the form of particles, powder, sheet, film, membrane, string, thread, etc.

Pulp particles can be produced by processing the obtained molded product appropriately or by crushing it into fibrils by applying a certain amount of cutting force until then. Various grinders, mills, pulverizers, etc. can be used as a method for applying the scale cutting force. Furthermore, this process is quite similar to the preparation in paper manufacturing, so various beaters, refiners, etc. are used.
Can be used. Furthermore, some of the crushers and grinders used in pulp production can also be used in the present invention.

Specifically, 1. Bringing the molten polyester into contact with a refrigerant such as water, and at the same time imparting a shearing force to the polyester using, for example, a homomixer. 2. Bringing the solid polyester into contact with water, methanol, ethanol, propanol, butanol, ethylene glycol, etc. Applying force to the trout in a crusher in the presence or absence of halogenated hydrocarbons such as alcohols, dichloroethane, trichlene, etc. 3 After stretching or rolling the solidified or solidifying molded product, or after heat treatment Examples of methods include applying scale-cutting force to break it into fipules.

By combining these various conditions, the characteristics of the pulp particles produced can be preferably controlled.
By selecting the structure of the polymer and more preferably the state of the melt to be molded, the present invention solves the problem of being easily oriented in the longitudinal direction and tearing in the parallel direction, which was previously thought to be a disadvantage of these rigid polymers. The present invention provides a new method for producing useful pulp particles by improving the problems of the method for forming films, threads, etc. according to the present invention.

In order to improve the mechanical properties and heat resistance of the polyester pulp particles of the present invention, the flow of the polyester is started at any stage after the polymerization of the polyester, for example, before applying a shearing force after polymerization or after forming the pulp particles according to a conventionally known method. The heat treatment can be carried out at a temperature below this temperature (for example, from 250 to 350 o'clock) under normal pressure to reduced pressure.

The pulp particles of the present invention may be formed into a sheet-like material such as heat-resistant insulating paper of class F or higher, if necessary, together with short fibers from the polyester used to produce the pulp particles of the present invention. I can do it.

It also has high mechanical properties, particularly high strength and modulus, and is therefore industrially useful as a lightweight resin reinforcement material.

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

Furthermore, since the pulp particles of the present invention are made of wholly aromatic polyester, they have excellent hydrolysis resistance, as well as excellent heat resistance and oxidation stability. suitable.

Example 1 Consisting of 75 mol% of p-oxybenzoin brewing component, 25 mol% of isophthalic brewing component, 25 mol% of 4,4'-dioxydiphenyl component, and has an intrinsic viscosity of 0.95 (however, 10 cc of p-oxybenzoin brewing component is 0.05 mol%).
Copolyester (value determined by dissolving in chlorophenol and measuring at 50°C) was heated and melted at 290°C and extruded from a slit die with a width of 2 mm and a thickness of 0.1 at a linear speed of 5.
It was pushed vertically downward at a speed of 1 h/min to pass through an air layer of approximately 1 ratio, and then introduced into water at room temperature, which was being traversed at high speed.

The extrudate was subjected to shearing force in this water, solidified and simultaneously fragmented to become fipulid-shaped pulp particles. When a small amount of the copolyester was placed on a sample stage of a polarizing microscope equipped with a heating cell and its melting state at 290qC was observed, the field of view was bright even under crossed Nicol conditions, and it was confirmed that it had optical anisotropy. Example 2
1p-oxybenzoin brewing component 60 mol%,
Diphenoxyethane-4,4'-dicarboxylic acid component 4
0 mol%, hydroquinone component 40 mol%, intrinsic viscosity 1.85 (however, 10 cc of 0.05 mol of polymer
Copolyester (value determined by dissolving in p-chlorpherol and measuring at 50°C) was melted by heating to 310°C, extruded into air at room temperature through the same slit die as in Example 1, and then By passing it between rolls, solidification and stretching were performed simultaneously to obtain a film-like molded product.

Fibrous pulp particles with relatively uniform shape and size were obtained by beating this film-like material with a beater. Further, by kneading this fibrous pulp with a so-called raw resin of unsaturated polyester and then aging it, a reinforced molded article in which particles were uniformly dispersed could be obtained. Example 3 p-oxybenzoin component 67 mol%, isophthalic component 28 mol%, carbonic acid component 5 mol%, hydroquinone component 3
3 mol%, intrinsic viscosity 1.50 (however, polymer 0
．． Value obtained by dissolving 0.05 in 10 cc of a mixed solvent of 2,4,6-trichlorophenol/2,4,5-trichlorophenol (weight ratio 5, Mura 50) and measuring at 35°C)
It was possible to easily prepare fibrous pulp particles by heating and melting the copolyester to 340 d0, extruding it into a thread through a nozzle with a diameter of 0.5 mm, introducing it into a homomixer, and crushing it. .

Example 4 An intrinsic viscosity of 1.6% by mole, consisting of 67% by mole of p-oxybenzoic acid, 33% by mole of isophthalic acid, and 33% by mole of hydroquinone.
80 (however, the value measured at 500○ by dissolving polymer 0.059 in 10 ccp-chlorophenol) was heated and melted at 35,000 °C to form an optically anisotropic melt. Fibrous pulp particles could be easily produced by inserting the filament into the air through a paper thread cap, placing it in a homomixer, and crushing the filament with water in a rope frame.

It was confirmed that this pulp particle did not shrink even when opened at 200o0 and had excellent heat resistance.

Claims (1)

[Claims] 1. A polyester characterized by melt-molding a wholly aromatic polyester that has the property of forming an anisotropic melt to form a molded product having molecular orientation, and crushing the molded product into fibrils by applying a shearing force. Method for producing pulp particles.