JPS61106631A - Production of colored polyester molding - Google Patents

Abstract

PURPOSE:To produce the titled molding of good color uniformity, by crystallizing at least either one of an uncolored pellet of a specified thermoplastic polyester or a colored master pellet, pre-mixing these two pellets together and molding the mixture after drying. CONSTITUTION:At least either one of an uncolored pellet of a thermoplastic polyester consisting mainly of ethylene terephthalate units or a colored master pellet of said polyester is crystallized to a crystallinity >=10% by heating in an atmosphere of any one of air, inert gas or high vacuum in, for example, a tray hot air dryer or a rotary dryer, mixed with each other, dried and molded. Because of uniform mixing, a molding of good color uniformity can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing colored polyester molded articles. More specifically, the present invention relates to a method for producing a molded article from uncolored thermoplastic polyester pellets and colored master pellets.

Conventional Technology Thermoplastic polyester has traditionally been used in clothing, films, bottles, etc. due to the material's excellent physical and chemical properties.
It is widely used for various purposes such as industrial materials. Some of these polyvarnish molded products often require coloring in order to provide additional properties such as decorative properties and light-shielding properties. To obtain a colored polyester molded product, first, a highly concentrated colored composition and polyester are kneaded in an extruder to create a master pellet, mixed with uncolored pellets to the desired concentration, and then dried. It is common to mold the material after a certain period of time.

Problems to be Solved by the Invention However, when colored master pellets and uncolored pellets are mixed before drying, the colored master pellets and uncolored pellets are often not mixed uniformly, and in extreme cases, they are not mixed completely. They will separate.

As a result, color unevenness occurred in the colored polyester molded product, making it difficult to obtain a uniformly colored molded product.

On the other hand, if you dry the colored master pellets and uncolored master pellets separately and then mix them together, you can mix them uniformly, but you will need two dryers, and you should also be careful about the moisture absorption of the pellets during mixing. have to pay the process,
Management becomes complicated and undesirable.

In view of the current situation, the present inventors have conducted intensive research on a method for uniformly mixing colored master pellets and non-colored pellets, and as a result, have arrived at the present invention.

The object of the present invention is to provide a method for industrially easily producing uniformly colored polyester molded articles without uneven color.

It is to serve.

Means for Solving the Problems The method of the present invention provides the method for preparing uncolored thermoplastic polyesters whose main repeating unit is ethylene terephthalate. When molding a colored polyester molded article, at least one of the pellets is crystallized to a crystallinity of 10% or more, mixed, dried, and then molded.

The thermoplastic polyester having ethylene terephthalate as a main repeating unit in the present invention usually has an acid component of 80 moles or more, preferably 90 moles or more of terephthalic acid, and a glycol component of 80 moles or more, preferably 90 moles or more. It means a polyester that is ethylene glycol, and other acid components include isophthalic acid, diphenyl ether 4,4 dicarboxylic acid, naphthalene 1,4-dicarboxylic acid, naphthalene 2,6-dicarboxylic acid, adipic acid, sebacic acid, and others. Glycol components include propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, cyclohexane dimetatool, 2,2'-bis(4-hydroxyphenyl)propane 1212'-bis(4-hydroxyethoxyphenyl)propane, or P-oxy as oxyacid,
It means a polyester containing cybenzoic acid, ]P-hydroethoxybenzoic acid, etc. The intrinsic viscosity of the thermoplastic polyester used in the present invention is usually 0.5 to 2.01, preferably 0.6 to 1.5. Note that the intrinsic viscosity is a value measured at 20° C. using a mixed solvent of phenol/tetrachloroethane (60/40 weight ratio).

Furthermore, the colored master pellet obtained from the thermoplastic polyester of the present invention means a pellet obtained by melt-kneading a coloring agent into the thermoplastic polyester whose upper repeating unit is ethylene terephthalate. The coloring agents used in the present invention are azo-based, polyazo-based, anthraquinone-based, quinacridone-based, perylene-based, perinone-based, phthalocyanine-based, flavanthrone-based, and quinophthalone-based.

and dioxazine-based organic dyes and pigments! ! Inorganic pigments such as iron dioxide, titanium oxide, ultramarine blue, yellow lead, and cadmium pigments and carbon black may be used alone, or a combination of two or more of these dyes and pigments may be used. It is preferable to disperse the colorant as uniformly as possible, and if necessary, it is also preferable to add a small amount of metal soaps such as zinc stearate and calcium stearate, and amide compounds such as ethylene bisstearamide.

The dye/pigment content of the colored master pellets used in the present invention varies depending on the type of dye/pigment, the amount of uncolored pellets to be blended, etc., but is usually 0.01 to 50%, preferably 0.1 to 10%. be. The amount of colored master pellets to be added to uncolored pellets varies depending on the dye/pigment content of the colored master pellets, but usually 2 to 10 uncolored pellets are added to 1 part by weight of master pellets.
0 parts by weight, preferably 5 to 30 parts by weight.

Crystallization in the present invention involves heating pellets in air, inert gas, or high vacuum, with or without stirring, such as in a tray hot air dryer,
There are rotary dryers, hopper dryers, etc.

The heat treatment is usually carried out at 100 to 180°C for about 0.5 to 10 hours. In the method of the present invention, it is necessary to crystallize either the colored master pellets or the uncolored pellets to a crystallinity of 10 cm or more.
It is advisable to crystallize only the colored master pellets.

If the degree of crystallinity of the crystallized pellets is less than 10 degrees, the uniform mixing of the pellets, which is a feature of the present invention, cannot be achieved. Here, the crystallinity is determined from the density of the pellet. The density is measured by a density gradient tube method using n-hebutane as a light liquid and carbon tetrachloride as a heavy liquid, and the degree of crystallinity is calculated from the density using the following formula.

However, d is the density of the sample, da is the density of the amorphous part 1.3
30 (P/cm), dk is the density of the crystal part 1.45
5 (k et al. 8).

According to the present invention, at least one of the uncolored pellets and the colored mask pellets is pre-crystallized, mixed, and then dried to uniformly mix them, and the result is 1) chestnut color. A molded product with no unevenness can be obtained. Furthermore, 1 (Usually, the amount of colored master pellets is smaller than that of non-colored pellets, so if only the colored master pellets are crystallized, a uniform colored polyester molded product with no uneven color can be easily obtained.

Example Hereinafter, the present invention will be explained in detail with reference to Examples.

Example 1 Thermoplastic polyester resin with an intrinsic viscosity of 0.70 (hereinafter referred to as P
ET) 100 parts by weight and Phthalocyanine Green 0.2
! After mixing with the mixing part and melting and kneading to obtain uniform high concentration matter pellets, the colored master pellets were mixed with
It was heat-treated at 0° C. for 1 hour and crystallized to a degree of crystallinity of 30°. Next, add 10 parts of this colored master pellet and the intrinsic viscosity is 0.
．． 70 and 7200 parts of the above PE in a tumbler,
After mixing for 1 hour, the pellets were uniformly mixed.

The mixed pellets were continuously put into a dryer and heated to 160°C.
After drying for 4 hours with
A biaxially stretched bottle with an internal volume of 1000 d was molded using a 50 mm stretch blow molding machine. l.

This bottle was uniformly colored green, with no uneven color.

Example 2 200 parts of PET pellets with an intrinsic viscosity of 0.70 were heat-treated at 130°C for 1 hour, and 10 parts of the same green colored master pellets as used in Example 1 were prepared without crystallization. I prepared the pellets, put them in a tamp and a larder, and mixed them for an hour, and the pellets were even.

- It was mixed with. Next, the mixed pellets were continuously put into a dryer, and the internal volume was reduced to 1000 in the same manner as in the example.
A biaxially stretched bottle of rnl was obtained. This bottle was uniformly colored green, with no uneven color.

Comparative Example 1 When pellets were mixed in exactly the same manner as in Example 1 except that the colored master pellets were not crystallized, the colored master pellets adhered to the tumbler wall surface and were not mixed uniformly. . Further, the pellets were dried in the same manner as in Example 1 and then stretch-blow molded to obtain a two-wheeled stretched bottle, but the bottle had uneven color and was poor in commercial value.

Procedural amendment 1, Indication of the case Patent Application No. 228269 of 1982, Name of the invention Method for producing colored polyester molded products 3, Person making the amendment Relationship to the case Patent applicant address 17 Sumida 5-chome, Sumida-ku, Tokyo Number 4 〒584
1-5-90 Tomobuchi-cho, Bejima-ku, Osaka City - Patent Department 6 of Boso Co., Ltd. Amends the description of the amendment as follows.

that's all

Claims (2)

[Claims] (1) When molding a colored polyester molded product from an uncolored thermoplastic polyester pellet whose main repeating unit is ethylene terephthalate and a colored master pellet of the polyester, the crystallinity of at least one of the pellets is 10% or more. 1. A method for producing a colored polyester molded article, which comprises crystallizing, mixing, drying, and then molding. (2) The method according to claim 1, wherein only the colored master pellets are crystallized.