JPH06172773A - Lubricant composition for polyalkylene terephthalate container - Google Patents

Abstract

PURPOSE:To obtain a lubricant composition which can inhibit or suppress the stress cracking of a PET container without detriment to the lubricating properties and can be suitably used as a lubricant for a bottle conveyor in the step of bottling, e.g. a carbonated drink into a PET container by adding an alkyldiphenyl ether disulfonate to a lubricant composition having a water-soluble alkali salt of a fatty acid as the principal component. CONSTITUTION:This lubricant composition is prepared by adding an alkyldiphenyl ether disulfonate of the formula (wherein R is 8-15 C alkyl; and M is sodium, potassium, ammonium or an alkanolamine group) to a lubricant composition for a polyalkylene terephthalate container containing a water-soluble alkali salt of a fatty acid as the principal component. This composition can inhibit or suppress the stress cracking of a PET container.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition used as a lubricant for a bottle conveyor in the step of filling a polyalkylene terephthalate container with, for example, a carbonated soft drink, and more particularly to a polyalkylene terephthalate while maintaining lubricity. The present invention relates to a lubricant composition for a polyalkylene terephthalate container capable of preventing or suppressing stress cracks in the container.

[0002]

2. Description of the Related Art In recent years, a polyalkylene terephthalate container (PET bottle) made of polyethylene terephthalate (PET) or the like has been used as a container for carbonated water such as carbonated soft drinks.
Is used. Further, a bottle conveyor is used for moving the containers in the step of filling the containers with the carbonated water.

These bottle conveyors are continuously operated by automatic control. Therefore, even if the flow of PET bottles is stopped, only the bottle conveyors are continuously operated as they are. In this case, the PET bottles are It is necessary to reduce the dynamic frictional force with the conveyor surface. Further, in order to put the PET bottle conveyed from the washing machine on the flow of the bottle conveyor as it is, an appropriate static friction force is required on the conveyor surface.

Conventionally, as a lubricant satisfying these needs, a lubricant composition containing a water-soluble fatty acid alkali salt as a main component and, if necessary, a surfactant such as a nonionic surfactant has been used. Are known. It was used by diluting it with water and supplying it on a bottle conveyor by means such as coating.

[0005]

However, although these lubricants maintain the lubricity satisfying the above-mentioned requirements, P
When attached to an ET bottle, the inside of the bottle is under pressure due to carbon dioxide gas and is under stress,
It causes stress cracks in the PET bottle,
For this reason, the PET bottle inevitably has a risk of damaging the bottle and a risk of leaking the beverage liquid filled in the bottle.

Therefore, an object of the present invention is to utilize PET as a lubricant for a bottle conveyor in the process of filling carbonated soft drinks, for example, while maintaining lubricity.
Can prevent or suppress the stress crack of T bottle,
It is an object of the present invention to provide a lubricant composition for a polyalkylene terephthalate container, in which the above-mentioned drawbacks existing in the known art are improved.

[0007]

In order to achieve the above-mentioned object, according to the present invention, a lubricant composition for a polyalkylene terephthalate container containing a water-soluble fatty acid alkali salt as a main component is further added to the above composition. , General formula

[Chemical 2] (Wherein R is an alkyl group having 8 to 15 carbon atoms, M is sodium, potassium, ammonium or an alkanolamine), and a stress crack of the polyalkylene terephthalate container is contained by containing an alkyldiphenyl ether disulfonate. It is characterized by preventing or suppressing.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail below. As a lubricant used in a bottle conveyor of a PET container, a lubricant containing a water-soluble fatty acid alkali salt as a main component and a surfactant if necessary is used as described above. The feature of the present invention resides in that such a known lubricant contains an alkyldiphenyl ether disulfonate.

The above-mentioned alkyl diphenyl ether disulfonates have the general formula

[Chemical 3] (However, R is an alkyl group having 8 to 15 carbon atoms, and M is sodium, potassium, ammonium, or an alkanolamine.) Specifically, Perex SSH (Kao Corporation), Sandet ALH (Sanyo Kasei Co., Ltd.) etc. are mentioned.

In the present invention, the content of the alkyl diphenyl ether disulfonate is at least 0.2 part by weight, preferably 0.2 to 3 parts by weight, based on 1 part by weight of the water-soluble fatty acid alkali salt in the composition. It is a department. If this amount is less than 0.2 parts by weight, the effect of preventing or suppressing stress cracks on the PET container is insufficient.

The water-soluble fatty acid alkali salt is a substance which exhibits a lubricating property used in ordinary lubricant compositions, and is a saturated or unsaturated fatty acid having 8 to 22 carbon atoms, sodium, potassium, ammonium, or It is an alkanolamine salt. Specifically, these are coconut oil fatty acids containing saturated fatty acids as a main component, lauric acid, oleic acid containing unsaturated fatty acids as a main component, or beef tallow fatty acid that is a mixture of saturated and unsaturated fatty acids, respectively, sodium salts, respectively. , Potassium salts, ammonium salts, or alkanolamine salts such as triethanolamine. These may be used alone or in combination in the present invention.

The above-mentioned lubricant composition of the present invention may further contain a surfactant such as a nonionic surfactant. This is to uniformly attach the lubricant component on the conveyor and to remove stains on the conveyor due to the water-insoluble component as an impurity in the water-soluble fatty acid alkali salt.
Preferred specific examples of this type include fatty acid alkanolamides, polyoxyethylene fatty acid esters, polyhydric alcohol fatty acid esters, polypropylene glycol ethylene oxide adducts, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, propylene oxide / ethylene. Examples thereof include nonionic surfactants such as oxide copolymers.

This blending amount is any appropriate amount sufficient to exert the above-mentioned advantages, but is preferably 0.2 to 1 part by weight with respect to 1 part by weight of the water-soluble fatty acid alkali salt. .

The thus obtained lubricant composition according to the present invention is adjusted to pH 6 to 10, and if necessary, a chelating agent, a bactericidal agent, a solubilizing agent, a defoaming agent and the like are added and mixed, It is used by diluting it with water to an appropriate dilution ratio, for example, 100 times to 200 times, and applying it on the bottle conveyor surface.

[0015]

The above-mentioned lubricant composition according to the present invention imparts lubricity by the action of the water-soluble fatty acid alkali salt component, and, if necessary, by the action of the surfactant component, the lubricant component is provided on the conveyor. Contamination on the conveyor due to water-insoluble components that are uniformly adhered and are included in the water-soluble fatty acid alkali salt as impurities is removed.

On the other hand, all of these components are substances that cause stress cracks in the PET container.
On the other hand, the above-mentioned alkyldiphenyl ether disulfonate used in the present invention can prevent stress cracks in the PET material in advance, and therefore the lubricant composition according to the present invention improves the lubricity of the bottle conveyor. It is possible to prevent or suppress stress cracks in the PET container while maintaining.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples.

[Examples] Samples 1 to 3 of each composition shown in Table 1
27 was adjusted to 100 parts by weight in terms of pure content and used as a test sample.
A stress crack test and a lubricity test were performed on each of these test samples, and the results are also shown in Table 1. The stress crack test and the lubricity test were performed as follows.

[Stress crack test] A PET container is filled with carbonated water and the pressure of 4.0-4.5 gas Vol (container capacity
Adjusted to 4.0-4.5 times the carbon dioxide pressure), PE for test
It was used as a T container. Then, each test sample in Table 1 was diluted 100 times with water, and the above-mentioned PET container for test was immersed therein in a semi-immersed state and left for 10 days at 40 ° C. and 80% humidity. After that, the state of occurrence of cracks in the PET container is visually observed and evaluated. The evaluation criteria are as follows. A: Complete or almost no cracks were generated. B: There are a few small cracks, but there is almost no crack. C: A large crack can be seen. D: There are many large cracks.

[Lubricity Test] (1) Test Conveyor Conditions Conveyor Speed: 30 to 90 cm / sec Test Bottle: One PET Container for Testing (Weight 1610)
g)

(2) Test method A PET container for testing was placed on a stainless steel conveyor plate, and then 25 ml / 100 ml or 200 times water dilution of each sample under test in Table 1 was placed on this conveyor plate.
The friction coefficient (μ) after 10 minutes when supplied in minutes,
The lubricity of each sample is evaluated.

Friction coefficient is a calculation formula

[Equation 1] Calculate using.

The evaluation criteria are as follows. A: 0.12 or less, very slippery. B: ~ 0.14 Sliding without problems C: ~ 0.16 Insufficient lubrication D: 0.16 or more Do not slip

[0024]

[Table 1]

As is clear from Table 1, sample No. 3, in which 0.2 parts by weight or more of alkyl diphenyl ether disulfonate was added to 1 part by weight of the water-soluble fatty acid alkali salt,
In all of 5 to 17, 21 to 23, and 26 to 27, the stress crack evaluation and the lubricity evaluation were ranks A to B, and good results were shown.

[0026]

INDUSTRIAL APPLICABILITY As described above, the lubricant composition according to the present invention has the lubricity by adding an alkyldiphenyl ether disulfonate to the lubricant composition containing a water-soluble fatty acid alkali salt as a main component. It is possible to prevent or suppress the stress crack of the PET container while maintaining the above, and therefore, the PET container is most suitable for use as a lubricant for bottle conveyors in the process of filling carbonated soft drinks and the like, and is a practically useful invention. is there.

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Claims (6)

[Claims] 1. A lubricant composition for a polyalkylene terephthalate container containing a water-soluble fatty acid alkali salt as a main component, wherein the composition further comprises a compound represented by the general formula: (Wherein R is an alkyl group having 8 to 15 carbon atoms, M is sodium, potassium, ammonium or an alkanolamine), and a stress crack of the polyalkylene terephthalate container is contained by containing an alkyldiphenyl ether disulfonate. A lubricant composition, which prevents or suppresses 2. The lubricant composition according to claim 1, wherein the content of the alkyl diphenyl ether disulfonate is at least 0.2 part by weight with respect to 1 part by weight of the water-soluble fatty acid alkali salt. 3. The lubricant composition according to claim 1, wherein the water-soluble fatty acid alkali salt is one or more of coconut oil fatty acid, lauric acid, oleic acid, or tallow fatty acid sodium, potassium, or alkanolamine salt, respectively. . 4. The lubricant composition according to claim 1, wherein the composition according to claim 1 further contains a surfactant. 5. The lubricant composition according to claim 4, wherein the surfactant is a nonionic surfactant. 6. The nonionic surfactant is a fatty acid alkanolamide, polyoxyethylene fatty acid ester, polyhydric alcohol fatty acid ester, polypropylene glycol ethylene oxide adduct, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether and propylene. The lubricant composition according to claim 5, which is one or more selected from the group of oxide / ethylene oxide copolymers.