JPS6366222A - Production of polyester - Google Patents

Abstract

PURPOSE:To obtain a polyester suitable as white films for substrates, e.g. card, label, white board, etc., by adding and reacting calcium carbonate and phosphorus compound at specific weight ratios with a dicarboxylic acid (derivative) and ethylene glycol. CONSTITUTION:In reacting (A) a dicarboxylic acid (ester-forming derivative), e.g. terephthalic acid, etc., with (B) ethylene glycol in a polyester reaction system to produce a polyester, (C) calcium carbonate having 0.05-5mum average particle diameter in an amount of 5-50wt% based on the resultant polyester and (D) a phosphorus compound, e.g. phosphoric acid, etc., at 0.0005-0.1mol ratio based on the component (C) and in an amount of preferably 0.01-2wt% based on the resultant polyester in the form of, e.g. a slurry of the component (B), are added to the polyester reaction system in any period to carry out polycondensation and afford the aimed polymer, which is then biaxially drawn to provide white films.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing polyester.

More specifically, it relates to a method for producing polyester by adding a specific amount of calcium carbonate and phosphorus compounds, and more specifically, it is suitable for use in white polynisder films used as substrates for cards, labels, display boards, white boards, etc. This is related to a method for producing polyester.

[Prior Art] Polyester represented by polyethylene terephthalate has excellent physical and chemical properties and is widely used as fibers, films, and other molded products. Among these uses, white films are particularly used as substrates for cards, labels, display boards, white boards, and the like.

Conventionally, it is well known to add a large amount of white inorganic particles to polyethylene terephthalate 1 to obtain a white film. For example, there are examples in which large amounts of titanium oxide and barium sulfate are added (Japanese Patent Publication No. 59-4901), and examples in which a large amount of barium sulfate is added (Japanese Patent Publication No. 30930-1983).

Further, Japanese Patent Publication No. 4.3-12013 discloses adding a large amount of calcium carbonate.

However, in the conventional technology mentioned above, it is difficult to disperse particles with barium sulfate added, and titanium oxide has a particle size of 380 m
Since it absorbs visible light below rr, when the obtained polyester is used to form a film, it is possible to obtain a film with sufficient whiteness and hiding power.

Furthermore, if a large amount of calcium carbonate is simply added to the polyester reaction system as exemplified in Japanese Patent Publication No. 43-12013, it is not preferable because particle aggregation may occur or 1q of strong yellowish polymer may be produced. do not have.

On the other hand, when a large amount of calcium carbonate is triblended with polyester during melt molding, bubbles are generated during melt extrusion, and a uniform film cannot be obtained.

[Problems to be Solved by the Invention] The purpose of the present invention is to add a specific amount of calcium carbonate and to improve the agglomeration of particles and deterioration of boria color tone that occur when a large amount of calcium carbonate is added to a polyester reaction system. Adopting a polyester manufacturing method in which a phosphorus compound with a constant m ratio of 1JI to calcium carbonate is added to calcium carbonate in combination can solve the above-mentioned conventional drawbacks.

[Means for Solving the Problems] The object of the present invention is to produce poly-[-sulfur] by the reaction of dicarbonate M-bb or its ester-forming derivative with ]-brene glycol. (A) Calcium carbonate with an average particle size of 0.05□ to 5μ is added to 1q of polyester in an amount of more than 5% by weight and less than 50% by weight J5J,
and (B) the phosphorus compound is added to the reaction system in a ratio of 0.0005 to 0.1 to calcium carbonate, and 0.01 to 2% relative to the obtained polyslull. This can be achieved by a method for producing polyester.

The polyester of the present invention is produced by transesterification or esterification reaction and polycondensation reaction between dicarboxylic acid or its ester-forming derivative and ethylene glycol.

The type of polyester is not particularly limited as long as it can be molded into fibers, films, and other molded products.

Suitable polyesters that can be formed into fibers, films, and other molded articles include those in which the dicarboxylic acid component is an aromatic dicarboxylic acid, such as polyethylene terephthalate, polyethylene-p-oxybenzoate, polyethylene-1,2- Bis(2-chlorophenoxy)ethane-4,4-dicarboxy μ-1~, polyethylene-1,2-bis(phenoxy)ethane-4,4-dicarboxylate, polyethylene-2,6-naphthalene dicar Examples include poxylates, among which polyethylene terephthalate is preferred. Of course, these polyesters may be homopolyesters or copolyesters, and examples of components to be copolymerized include diethylene glycol, neopentyl glycol, polyalkylene glycol with an average molecular weight of 150 to 20,000,
Diol components such as p-xylene glycol, 1,4-cyclohekylene dimethanol, 5-sodium sulforesorcin, adipic acid, sebacic acid, phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 5-sodium sulfoisophthalic acid Dicarboxylic acid components such as, polyfunctional carboxylic acid components such as trimellitic acid and pyromellitic acid,
Examples include oxycarboxylic acid components such as p-oxyethoxybenzoic acid.

Calcium carbonate as used in the present invention may be either a natural product or a synthetic product, and its crystal form includes calcite, aragonite, patellai 1, etc., but is not particularly limited.

In addition, calcium carbonate may not be surface-treated with stearic acid, polyacrylic acids, silane coupling agents, butane coupling agents, etc., and surfactants such as mono-lium dodecylbenzenesulfonate may be used in combination. Good too. It may also contain metal oxides such as magnesium oxide, aluminum oxide, silicon dioxide, etc.

Further, the average particle size of calcium carbonate needs to be 0.05 to 5μ, preferably 0.1 to 3μ, and more preferably 0.2 to 2μ. If the average particle diameter is less than 0.05μ, the dispersibility of the particles in polyester will be poor, and if the average particle diameter exceeds 5μ, if a film is formed, the film intended for the purpose of the present invention will not be obtained, such as poor hiding power. .

Generally speaking, the amount of calcium carbonate added in the present invention must be more than 5% by weight and not more than 50% by weight, preferably 7 to 40% by weight, and more preferably 10 to 30% by weight.

If the amount added is less than 5% by weight, when the resulting polynisdel is formed into a film, the intended white surface and hiding power of the film will be insufficient. If the amount added exceeds 50% by weight, the particle dispersibility in the polyester may be poor or the film strength may be insufficient.

The phosphorus compound as used in the present invention refers to a compound that contains a phosphorus atom and is glycol-soluble ↑ (1).

Examples include phosphoric acid, phosphorous acid, phosphonic acid, and derivatives thereof. Specifically, phosphoric acid, phosphorous acid,
Trimethyl Esral 2 phosphate, Tributyl phosphate, Trino T phosphate, Mono- or dimethyl phosphate, Trimethyl phosphite, Methylbosphonic acid, Dimethyl Z methylphosphonate [Sprue,
Examples include phenylphosphonic acid dimethyl ester and phenylphosphonic acid diethyl ester. Among these, use of phosphoric acid, phosphorous MQ d3 and ester-forming derivatives thereof is particularly preferred.

Furthermore, these phosphorus compounds may be used alone or in combination of two or more.

The amount of the phosphorus compound added in the present invention is 0.01 to 173% by weight based on 1q of polynisdel, and the molar ratio of the phosphorus compound to calcium carbonate is 0.0005 to 0.
．． The range is 1.

Further, the amount of the phosphorus compound added is preferably 0.07 to 1.5% by weight based on the obtained polyester, and the molar ratio of the phosphorus compound to calcium carbonate is 0.0015 to 0.00% by weight.
0.07, and the more preferable amount of the phosphorus compound added is 0.07.
1% to 1% by weight, and the molar ratio of the phosphorus compound to calcium carbonate is 0.003 to 0.05. If the molar ratio of the phosphorus compound to calcium carbonate is less than 0.0005, or the amount added is 0.0 for the polyester obtained
If it is less than 1% by weight, the dispersibility of calcium carbonate in the polyester will be poor, or the color tone of the obtained polyester will deteriorate, and when it is made into a film, it will not be able to obtain a sufficient white surface or softening power.

On the other hand, the molar ratio of phosphorus compound to calcium carbonate is 0
．． If the amount exceeds 1, or if the amount added exceeds 2% by weight based on the polynisdel to be obtained, the polymerization reactivity during polyester production may decrease, or by-product diethylene glycol may increase.

As mentioned above, the present invention aims to improve the dispersibility and color tone of calcium carbonate particles in polyester by adding a phosphorus compound to the polyester reaction system in a specific amount ratio to calcium carbonate. At the same time, when the obtained polyester is formed into a film, a white film with an excellent white surface and hiding power can be obtained.

The calcium carbonate and phosphorus compounds of the present invention may be added to the polyester reaction system at any time, preferably from before the esterification or transesterification reaction during polynisdel production to the early stage of polycondensation, and more preferably from before the esterification or transesterification reaction during the production of polynisdel. This period is from the end of the conversion or transesterification reaction to the beginning of the polycondensation reaction.

Additionally, the method of adding calcium carbonate and phosphorus compounds to the polyester reaction system is not limited to 1 hour;
Calcium carbonate and phosphorus compound may be added simultaneously or in a mixture. In order to obtain particularly good calcium carbonate dispersibility, a preferred addition method is to add calcium carbonate after adding the phosphorus compound, and the addition interval is within 1 hour, more preferably within 30 minutes.

Calcium carbonate and phosphorus compounds to be added to the polyester reaction system may be added in the form of powder or liquid, but from the viewpoint of the dispersibility of calcium carbonate in the polyester, organic solvents such as glycol, etc. It is preferable to add the compound in the form of a slurry or a liquid by appropriately mixing the compound and the like. Furthermore, the slurry or liquid may be added after being heat-treated.

In addition, the polyester of the present invention may contain metal compound catalysts such as lithium, sodium, calcium, magnesium, manganese, zinc, cobalt, antimony, germanium, and titanium, which are commonly used during production, antioxidants, pigments, fluorescent brighteners, and surfactants. If necessary, antistatic agents, antistatic agents, and even inorganic particles other than calcium carbonate can be added as appropriate.

When producing a film from the polyester to which calcium carbonate and phosphorus compounds of the present invention have been added, the polyester is formed into a sheet by a conventional method, and the polyester is formed into a sheet with a thickness of 2.5 to 4.5 mm in each biaxial direction. 15 after stretching 0 times
It is manufactured by heat setting at a temperature of 0°C or lower.

The preferred density of the biaxially stretched film using polyester produced by the production method of the present invention is 1,10 to 1.
38y/f, more preferably 1.15-1.35y/f
It is fl. If the density is less than 1.10, the mechanical properties of the film will be poor, and if the density exceeds 1.38, a desirable white surface of the film will not be obtained.

1 with the method of the present invention! 7. The polyester can be preferably used in molded products other than films, such as fibers in any field.

[Example] Hereinafter, the present invention will be explained based on examples and further along the shoreline.

Note that the characteristics in the examples were measured as follows.

A. Intrinsic viscosity of polymer Measured at 25°C using 0-chlorophenol as a solvent.

B. Softening point of polymer The polymer chip was placed in a heating bath and heated at 6°C for 15 minutes, and the temperature at which the tip of the load penetrated into the chip by 5# or more was measured.

C, Particle dispersion in polymer 20my of polymer was sandwiched between two cover glasses, 28
After melt press cooling at 0'C, judgment was made by microscopic observation.

The judgment criteria are as follows.

○: Almost no aggregated particles are observed. (Within the objective range of the present invention.) Δ: Slightly aggregated particles are observed. (The object of the present invention is not achieved.) X: Many aggregated particles are observed. (The purpose of the present invention is not achieved.) D. Polymer color tone = 12 - Hunter value (L, a
, b).

◎: white and white surface 0 or more (particularly preferred within the objective range of the present invention) ○: white and white surface 5 or more and less than 70 (within the objective range of the present invention) Δ; white and white surface 3 or more and less than 55 (this invention (The purpose of the present invention is not achieved.) ×; White surface is less than 53 (The purpose of the present invention is not achieved.)

F. Film hiding power Macbeth transmission densitometer TD-50/I, thickness 150
The visible light transmission density of the μ film was measured to determine the hiding power.

Transmission density [-] X: Less than 0.4 (poor hiding power) △; 0.4~
Less than 0.7 (hiding or poor) 010.7 to less than 1.0 (good hiding power) 011.0 or more (very good hiding power) The transmission temperature here is calculated from the following equation.

Example 1 After transesterifying 85 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol using 0.09 parts by weight of calcium acetate as a catalyst, transesterification was carried out according to a conventional method. An ethylene glycol solution containing 10% by weight of trimedel phosphate was added so that the molar ratio to calcium was 0.0130), and after 10 minutes, a slurry containing 40% by weight of calcium carbonate with an average particle size of 0.9μ was prepared. 37.5 parts by weight were added, and then 0.03 parts by weight of antimony trioxide was added as a polymerization catalyst.

Thereafter, a polycondensation reaction was carried out according to a conventional method under high temperature and reduced pressure to obtain a product with an intrinsic viscosity of 0.643 and a softening point of 25 g.

1q of polyethylene derephthalate at 7°C. As a result of observing the particle dispersion state of calcium carbonate in the polymer, no aggregated particles were observed. Furthermore, the color tone of the 1q polymer was very high with a white surface of 71.1 and had very little yellowness, which was good.

0.03 parts by weight of fluorescent whitening agent "0B-1" (Gose 1 to Manufactured by Mann) was added to 1'OO"l of the obtained polyester, and the size was 3.2 times the length and 3 times the width according to the usual method. .2 times biaxial stretching was carried out to obtain a film with a thickness of 150 μm.The obtained film had a density of 1°30, had no defects such as air bubbles, and had excellent whiteness and hiding power.

Example 2 Polyethylene terephthalate 1- was obtained in the same manner as in Example 1 except that calcium acid salt having an average particle size of 0.4 μm and a phosphorus compound were mixed in advance and then added to the polyester reaction system. Both particle dispersibility in the polymer and color tone were excellent.

Further, a film was produced in the same manner as in Example 1, and the film had no defects such as bubbles and had excellent brightness and hiding power.

Comparative Example 1 Polyethylene terephthalate was obtained in the same manner as in Example 1 except that calcium having an average particle size of 0.04 μm was used. As a result of observing the particle dispersion state of calcium carbonate in the polymer, many aggregated particles were observed in the polymer. A film was produced using the polyester in the same manner as in Example 1. Coarse protrusions appeared on the surface of the film due to aggregated particles, and the hiding power of the film was somewhat poor.

Examples 3 to 9, Comparative Examples 2 to B Polyesters and films were produced in the same manner as in Example 1, except that the added calcium carbonate and phosphorus compounds were changed as shown in Table 1. The results are shown in Table 1.

Examples 3 to 9 were within the scope of the present invention, and were excellent in both particle dispersibility and color tone, and the films made from the polyester had no bubble defects and had good whiteness and hiding power.

On the other hand, in Comparative Example 2, the average particle diameter of calcium carbonate was outside the range of the present invention, and was 1! -7 Films made from polyester have poor hiding power and large film surface protrusions.

In Comparative Example 3.4.5.6, the molar ratio of the phosphorus compound to calcium carbonate and the amount added were outside the range of the present invention, and many aggregated particles were observed in the 1q polynisdel, and the whiteness was low. However, there were drawbacks such as a strong yellowish polymer, a decrease in polycondensation reaction P1, and a decrease in softening point.

Comparative Examples 7 and 8 had drawbacks such as poor film hiding power and poor particle dispersibility because the amount of calcium added was outside the range of the present invention.

Example 10 1 to 85 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol were subjected to a transesterification reaction using 0.09ffi parts of calcium acetate as a catalyst in accordance with a conventional method, and then calcium carbonate having an average particle size of 0.9μ was obtained. 40% by weight
37.5 parts by weight of the ethylene glycol slurry contained therein was added.

After 15 minutes, 0°273 to the polymer as a phosphorus compound
Weight% (molar ratio to calcium carbonate 0.0130)
An ethylene glycol solution containing 10% by weight of trimethyl phosphate was added so that the following was obtained, and then 0.03 part by weight of antimony trioxide was added as a polymerization catalyst.

Thereafter, a polycondensation reaction was carried out according to a conventional method under high temperature and reduced pressure to obtain polyethylene terephthalate having an intrinsic viscosity of 0.638 and a softening point of 259.degree. 6.degree. As a result of observing the particle dispersion state of calcium carbonate in the polymer, almost no aggregated particles were observed.

Moreover, the color tone of the obtained polymer was 61.0 on a white scale, and had a preferable color tone with little yellowish tinge. Add 0.03 parts by weight of fluorescent whitening agent "0B-1" (Eastman formal wear) to 100 parts by weight of 1q polyester, and add 3 parts vertically according to the usual method
．． Biaxial stretching was performed 2 times and 3.2 times in the width direction to obtain a film with a thickness of 150 μm. The obtained film had a density of 1.31, had no defects such as bubbles, and had excellent whiteness and hiding power.

[Effects of the Invention] As described above, the present invention has a specific amount and a specific amount ratio of calcium carbonate and phosphorus compounds having an average particle diameter of 0.05 to 5μ, by adding them to a polynisder reaction system, thereby producing a compound that has not been previously obtained. A polyester that does not contain aggregated particles, has a high white surface, and has little yellowing can be obtained.

When the polyester obtained by the production method of the present invention is formed into a film, it is possible to reduce clogging in the melt film forming process, prevent bubble generation during melt extrusion, and eliminate film tearing, as well as = 20-1 polishing and concealment. We can produce white films with excellent strength, which can be used for photographic paper, X-ray intensifying screens, cards, labels, display boards,
It is preferably used as a base material for whiteboards, decorative purposes, etc.

Claims (1)

[Claims] When producing polyester by the reaction of dicarboxylic acid or its ester-forming derivative with ethylene glycol, (A) is added at any stage of the polyester production process.
More than 5% by weight and not more than 50% by weight of the polyester capable of obtaining calcium carbonate with an average particle diameter of 0.05 to 5μ, and (B) a phosphorus compound in a molar ratio of 0.0005 to 0.1 to calcium carbonate, A method for producing polyester, which comprises adding 0.01 to 2% by weight of the obtained polyester to the reaction system.