JPH05230239A - Antistatic anti-fogging polyester sheet having good transparency - Google Patents

Abstract

PURPOSE:To obtain the title sheet which is excellent in antistatic effect or in both antistatic and anti-fogging effects and well retains the effect(s) by incorporating a derivative of a metal alkylbenzenesulfonate into a polyester having an ethylene terephthalate unit as the main repeating unit and melt-extruding the mixture. CONSTITUTION:100 pts.wt. polyester having an ethylene terephthalate unit as the main repeating unit is mixed with 0.1-3.5 pts.wt. derivative (a) of a metal alkylbenzenesulfonate and the mixture is melt-extruded to obtain the title sheet. In producing a single-layer sheet, the polyester is mixed desirably with 0.2-2.0 pts.wt. derivative of a metal alkylbenzensulfonate in which the alkyl is 10-14C, more desirably with 0.3-1.7 pts.wt. sodium dodecylbenzenesulfonate, to thereby enable the film to combine good antistatic properties and transparency. In the case of a multilayered sheet, the derivative (a) is incorporated into at least a surface layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoplastic polyester sheet having excellent antistatic property or antistatic property and antifogging property and excellent transparency.

[0002]

2. Description of the Related Art Generally, a sheet made of a thermoplastic resin is
The product that is easily charged and processed by processing the sheet for that purpose not only harms the appearance by adsorbing dust and dust on the surface, but also thermoforms it because the sheets are attracted to each other due to being charged with static electricity. However, there was a problem that it interfered with the handling of other molded products.

Conventionally, in order to solve such a problem,
A method of applying an antistatic agent to the surface of a sheet, a method of kneading an antistatic agent into a thermoplastic resin material to form a sheet, and the like have been performed. However, in the method of applying the antistatic agent to the surface of the sheet, the antistatic agent is likely to be peeled off by touching the mold during cleaning or thermoforming, and the antistatic effect is easily lost. In addition, the printability, adhesiveness, heat sealability, etc. of the sheet are impaired, and the post-processability is reduced. On the other hand, the method of kneading an antistatic agent into a sheet to form a sheet is one in which the antistatic agent kneaded into a thermoplastic resin is formed into a sheet and then eluted on the surface of the sheet to produce an antistatic effect. .. However, the elution phenomenon of the antistatic agent to the sheet surface itself is a phenomenon caused by the incompatibility between the thermoplastic resin and the antistatic agent, so the antistatic agent eluted on the sheet surface can be easily removed from the sheet surface. take off. Since the fallen antistatic agent is covered, it takes time to elute from the inside of the sheet, and the antistatic effect decreases during that time.
If the antistatic agent is added until the antistatic effect is sufficiently exerted, the transparency characteristic of the polyester sheet is impaired.

In general, a polyester film is stretched in one or two directions in order to shorten the time required for elution of the antistatic agent, so that a large amount of the antistatic agent is eluted on the surface of the sheet. It is also trying to improve transparency by further stretching and thinning.

[0005]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of intensive investigations by the present inventors, a polyester sheet having excellent antistatic effect or antistatic effect and antifogging effect, and having a continuous effect and transparency is obtained. The present invention has been reached. That is, the present inventors have used an alkylbenzene sulfonic acid metal salt derivative, preferably an alkyl group having 10 to 14 carbon atoms, and more preferably having 12 carbon atoms of sodium dodecylbenzene sulfonate, in an amount of 0.1 to 2 per 100 parts by weight of polyester. .0
By blending parts by weight, it was possible to obtain a sheet having the desired antistatic property and transparency. As a result of further study, the present inventors have found that the alkylbenzene sulfonic acid metal salt derivative is 0.7 to 3.5 parts by weight, preferably 1.2 to 2.0 parts by weight in a single layer and 1.2 to 3 in a multilayer. It has been found that when it is blended in an amount of 0.5 part by weight, it also exhibits excellent antifogging properties.

[0006]

The above object is to add 0.1 to 3.5 parts by weight of an alkylbenzene sulfonic acid metal salt derivative to 100 parts by weight of a polyester having ethylene terephthalate units as main repeating units, This is accomplished with a melt extruded polyester sheet.

The present invention will be described in detail below. The polyester used in the present invention is a thermoplastic polyester resin having an ethylene terephthalate unit as a main repeating unit (usually 80 mol% or more), and specifically, polyethylene terephthalate, isophthalic acid, adipic acid, polyethylene glycol, 1,4 Examples thereof include butanediol and a copolymer of 1,4 cyclohexanedimethanol.

The polyester sheet of the present invention is obtained by melt-extruding the above polyester resin by a known method such as a T-die method or an inflation method, and may be a single layer or a multilayer, and the sheet thickness Saha is usually 0.15
~ 3 mm. The present invention relates to the above polyester sheet 10
0.1 to 3.5 parts by weight of the alkylbenzene sulfonic acid metal salt derivative is mixed with 0 part by weight, but in the case of a single layer sheet, preferably, the alkylbenzene sulfonic acid metal salt derivative having an alkyl group having 10 to 14 carbon atoms is 0.2 to By blending 2.0 parts by weight, more preferably 0.3 to 1.7 parts by weight of sodium dodecylbenzenesulfonate having 12 carbon atoms, a polyester sheet satisfying both antistatic property and transparency can be obtained.
For the purpose of imparting antifogging property, 1.2 to 2.0 parts by weight is preferable.

In the case of a multi-layered sheet, it is preferable to blend an alkylbenzene sulfonic acid metal salt derivative on at least one side of the sheet. In this case, the upper limit of the blending amount, which is limited by the transparency, is relaxed as the thickness of the sheet decreases, so the blending amount is 0.3 to 3.5 parts by weight.
For the purpose of imparting antifogging property, 1.2 to 3.5 parts by weight is preferable.

In the present invention, in order to improve the slipperiness of the sheet, an organic silicon smoothing agent may be applied or a fine particle lubricant may be added.

[0011]

INDUSTRIAL APPLICABILITY As described above, the polyester sheet of the present invention contains the alkylbenzene sulfonic acid metal salt derivative of 0.1.
By blending 1 to 3.5 parts by weight, it is excellent in antistatic property or antistatic property and antifogging property, and also excellent in transparency, and is a container, blister or bent that is thermoformed by vacuum forming or pressure forming. It is useful for cases such as. In particular, the sheet imparted with antifogging property is useful as a food container.

[0012]

【Example】

Example 1 With respect to 100 parts by weight of polyethylene terephthalate resin,
Add 1 part by weight of sodium dodecylbenzene sulfonate,
Melt extrusion was performed through a T-die with a 75 mmφ single-screw extruder according to a conventional method to prepare a sheet having a thickness of 0.25 mm, and the following items were tested.

Transparency (haze): Sheet thickness 0.25 m
Measured using a Nippon Denshoku Industries NDH Σ80 color measuring system at m. The sheet of the present invention usually has a haze of 12 or less, preferably 8 or less. Anti-static property: Wool cloth on the sheet surface 20 times (about 1 time / se
c) 2.5c on dry tobacco ash after 10 seconds of rubbing
The state of adsorption of ash by static electricity was observed by approaching m. When the ash was attached by suction, it was rated as ×, and when it was not attached, it was rated as ○. Anti-fogging property: 250 ml of 50 ° C. warm water was put in a 300 ml wide-mouth glass cup, the sheet was covered under an atmosphere of 23 ° C. and 65 RH, and the cloudy state after 1 minute was observed, and the evaluation of Table 1 was performed. Surface resistance: Measured with Yokogawa Electric HIGE RESISTANCE METER 4329A and Toa Denpa Kogyo's electromagnetic shield box with weight electrode.

[0014]

[Table 1]

Example 2 Using the same resin and antistatic agent as in Example 1, a sheet was prepared and tested in the same manner as in Example 1 except that the amount of antistatic agent added was 2 parts by weight.

Example 3 A sheet having a thickness of 0.25 mm was prepared in which a polyethylene terephthalate resin was used as an intermediate layer and 100 parts by weight of the polyethylene terephthalate resin was mixed with 2 parts by weight of sodium dodecylbenzenesulfonate as upper and lower surface layers. do it,
The same test was performed (thickness ratio 1: 8: 1).

Then, a salad container was manufactured from the sheet by vacuum thermoforming, filled with potato salad, and stored in a refrigerator at 5 ° C. for 1 hour. No cloudiness was observed.

Comparative Example 1 A sheet was prepared in the same manner as in Example 1 using only the resin of Example 1.

Comparative Example 2 A sheet was prepared in the same manner as in Example 1 except that 1 part by weight of an antistatic agent containing a polyhydric alcohol fatty acid ester as a main component was added to the resin of Example 1.

Comparative Example 3 A sheet was prepared in the same manner as in Example 1 except that 1 part by weight of an antistatic agent containing diglycerin fatty acid ester as a main component was mixed.

Comparative Example 4 A polyester sheet was prepared in the same manner as in Example 1 except that 4 parts by weight of sodium dodecylbenzenesulfonate was added.

The sheets containing sodium dodecylbenzene sulfonate of Examples 1, 2 and 3 have a good haze and a large antistatic effect, and Examples 2 and 3 have a large antifogging effect. In Comparative Example 1 in which the antistatic agent is not added, the transparency is good, but the antistatic effect and the antifogging effect are poor. The polyhydric alcohol fatty acid ester-based antistatic agent of Comparative Example 2 and Comparative Example 4 have good antistatic effect and antifogging effect, but haze becomes very poor. Further, the diglycerin fatty acid ester antistatic agent of Comparative Example 3 had good transparency, but the antistatic effect and antifogging effect were insufficient. Table 2 summarizes the measurement results of the above Examples and Comparative Examples.

[0023]

[Table 2]

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Claims (2)

[Claims] 1. An alkylbenzene sulfonic acid metal salt derivative of 0.1 to 3 parts by weight per 100 parts by weight of a polyester containing ethylene terephthalate units as a main repeating unit.
5 parts by weight of a melt-extruded polyester sheet. 2. The alkylbenzene sulfonic acid metal salt derivative is sodium dodecylbenzene sulfonate.
The listed sheet.