JPH07310085A - Lubricant composition for polyalkylene terephthalate container - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing a water-soluble alkali salt of a fatty acid as a principal component and further a specific active component blended therewith and capable of preventing or suppressing the stress crack of a polyalkylene terephthalate container while maintaining the lubricity. CONSTITUTION:This composition is obtained by blending (A) a water-soluble alkali salt of a fatty acid (e.g. sodium oleate or triethanolamine salt of coconut oil fatty acid) as a principal component with further (B) an alkali salt of rosin and/or an alkali salt of a disproportionated rosin in an amount of preferably 0.1-1.5 pts.wt. based on 1 pt.wt. component (A). The alkali salt of the rosin which is the component (B) is usually preferably obtained by neutralizing a resin acid such as gum rosin with an alkali. The alkali salt of the disproportionated rosin is preferably prepared by heating the gum rosin, etc., in the presence of a catalyst and then neutralizing the resultant substance with an alkali. The composition is preferably used by a method for regulating the pH to 6-10, as necessary, adding a chelating agent, a germicide, etc., thereto, subsequently diluting the obtained mixture with water and coating the surface of a bottle conveyor with the diluted mixture.

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.

The present applicant has, as an invention in which the above-mentioned drawbacks have been eliminated, a lubricant composition in which an alkyldiphenyl ether disulfonate having a specific structural formula is contained in a lubricant containing a water-soluble fatty acid alkali salt as a main component. Has already been developed and is being applied for as a prior application of Japanese Patent Application No. 4-351579.

The present invention is a further improvement of the above-mentioned prior invention, in which a new active ingredient is used in place of the above-mentioned alkyldiphenyl ether disulfonate.

That is, the object of the present invention is to use P as a lubricant for a bottle conveyor in the process of filling a PET bottle with a carbonated soft drink, for example, while maintaining lubricity.
It is an object of the present invention to provide a lubricant composition for a polyalkylene terephthalate container, which can prevent or suppress stress cracks in an ET bottle and which has improved the above-mentioned drawbacks in the known art.

[0009]

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. , An alkali salt of rosin and / or an alkali salt of an asymmetric rosin compound are contained to prevent or suppress stress cracks in the polyalkylene terephthalate container.

[0010]

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 alkali salt of rosin and / or an alkali salt of an asymmetric rosin compound.

The above-mentioned rosin alkali salt is generally obtained by neutralizing a resin acid as a main component with an alkali. More specifically, as the resin acid, gum rosin obtained by distilling turpentine oil from raw pine resin in pine trees, benzene from pine chips, rosin after extracting the rosin component with a solvent such as alcohol, the solvent And wood rosin obtained by distilling off the crude oil, and tall rosin obtained by subjecting crude tall oil to vacuum distillation with a precision distillation column. The main component of these is abietic acid, and in addition, it contains one or more kinds of organic acids such as neoabietic acid, dehydroabietic acid, pimaric acid, isopimaric acid, and parastophosphoric acid.

Further, the above-mentioned alkali salt of asymmetric rosin is an alkali-neutralizing substance of the product obtained by heating the above-mentioned gum rosin, wood rosin, or tall rosin in the presence of a catalyst, the main component of which is alkali dehydroabietic acid. It is a mixture of a salt and an alkali salt of dihydroabietic acid, and specific examples thereof include an alkali-neutralizing substance such as hartol rosin (tall rosin) and bandis (asymmetrical compound) (both manufactured by Harima Kasei Co., Ltd.).

In the present invention, the above-mentioned rosin alkali salt and rosin asymmetrical alkali salt are used alone or in combination. The content thereof is at least 0.1 part by weight, preferably 0.1 to 1.5 parts by weight, based on 1 part by weight of the water-soluble fatty acid alkali salt in the composition. If this amount is less than 0.1 part by weight, the effect of preventing or suppressing stress cracks on the PET container will be somewhat inadequate, and if it is more than 1.5 parts by weight, especially 2 parts by weight, the lubricating performance will decrease somewhat. It is also possible to do it.

The above-mentioned water-soluble fatty acid alkali salt used in the present invention is a substance exhibiting lubricating performance used in ordinary lubricant compositions, and is a saturated or unsaturated fatty acid having 8 to 22 carbon atoms, An ether carboxylic acid having an alkyl group or an ethylene oxide addition ether carboxylic acid having an alkyl group of these fatty acids is a sodium salt, a potassium salt, an ammonium salt, or an alkanolamine salt such as triethanolamine. The above-mentioned saturated or unsaturated fatty acid having 8 to 22 carbon atoms is coconut oil fatty acid having saturating fatty acid as a main component, lauric acid, oleic acid having an unsaturated fatty acid as a main component, or a mixture of saturated and unsaturated fatty acids. It is a fatty acid. The addition of ethylene oxide is preferably 1 to 8 mol. The ethylene oxide-added ether carboxylic acid in this range has improved solubility, is hardly affected by hard water, and has no deterioration in lubricity. In the present invention, these alkali salts may be used alone or in combination of two or more.

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 it 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, etc. 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.

[0018]

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. The stains on the conveyor are removed by the water-insoluble components that are uniformly attached and that are contained in the water-soluble fatty acid alkali salt as impurities.

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 alkali salt of rosin or alkali salt of rosin asymmetrical compound used in the present invention can prevent stress cracks of the PET material, and therefore, the lubricant composition according to the present invention is a bottle. It is possible to prevent or suppress stress cracks in the PET container while maintaining the lubricity of the conveyor.

[0020]

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 1 of each composition shown in Table 1
18 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 the gas is 4.0 to 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: Somewhat large cracks can be seen, but practical use is possible. D: Many large cracks are not practical.

[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 PET container was placed on a stainless steel conveyor plate, and then 100 ml or 200 times water dilution of each sample under test in Table 1 was added to the conveyor plate at 25 ml /
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

[0027]

[Table 1]

As is clear from Table 1, sample No. 1 containing neither rosin alkali salt nor rosin asymmetrical alkali salt.
Nos. 3 to 3 cannot be put to practical use because the stress crack evaluation is poor. On the other hand, with respect to 1 part by weight of the water-soluble fatty acid alkali salt, sample Nos. 6 to 17 in which 0.1 part by weight or more of the rosin alkali salt or the rosin asymmetrical alkali salt was added, particularly sample Nos. 6 to 9, In each of Nos. 11 to 17, both the stress crack evaluation and the lubricity evaluation were ranks A to B, showing good results. In addition, in sample Nos. 4 and 5 containing 0.1 parts by weight or less of the rosin asymmetrical alkali salt, the stress crack evaluation was rather poor, and in addition, sample NO.1 containing 1.5 parts by weight or more was used.
At 0, the evaluation of lubricity is a little bad, but there is no problem in practical use.

[0029]

As described above, the lubricant composition according to the present invention is obtained by adding a rosin alkali salt or a rosin asymmetrical alkali salt to a lubricant composition containing a water-soluble fatty acid alkali salt as a main component. It is possible to prevent or suppress stress cracks of a PET container while maintaining lubricity, and therefore, it is most suitable for use as a lubricant for bottle conveyors in the process of filling a PET container with, for example, carbonated soft drinks, and is practically useful. It is an invention.

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Claims (10)

[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 contains an alkali salt of rosin and / or an alkali salt of an asymmetric rosin compound. A lubricant composition which prevents or suppresses stress cracks in the polyalkylene terephthalate container. 2. A gum rosin obtained by distilling turpentine oil from raw pine resin, a wood rosin obtained by solvent extraction from pine chips, or a tall rosin obtained by precision fractionation from crude tall oil. The lubricant composition according to claim 1, wherein the lubricant composition is an alkali neutralizing substance. 3. The lubricant composition according to claim 2, wherein the alkali neutralizing substance according to claim 2 contains an alkali salt of abietic acid as a main component. 4. An alkali salt of abietic acid as a main component of the alkali-neutralizing substance according to claim 3, neoabietic acid,
The lubricant composition according to claim 3, which is one or a mixture of one or more organic acid alkali salts selected from the group of dehydroabietic acid, pimaric acid, isopimaric acid and parastophosphoric acid. 5. The rosin asymmetrical alkali salt is obtained by precision fractionation of gum rosin obtained by distilling turpentine oil from raw pine resin, wood rosin obtained by solvent extraction from pine chips, or crude tall oil. The lubricant composition according to claim 1, which is an alkali-neutralizing substance of a product obtained by heating the obtained tall rosin in the presence of a catalyst. 6. The lubricant composition according to claim 5, wherein the alkali-neutralizing substance of claim 5 comprises a mixture of an alkali salt of dehydroabietic acid and an alkali salt of dihydroabietic acid as a main component. 7. The content of the rosin alkali salt and / or rosin asymmetric alkali salt of claim 1 is at least 0.1 part by weight per 1 part by weight of the water-soluble fatty acid alkali salt in the composition. The lubricant composition of 1. 8. The content of the rosin alkali salt and / or rosin asymmetric alkali salt of claim 1 is 0.1 to 1.5 parts by weight with respect to 1 part by weight of the water-soluble fatty acid alkali salt in the composition. A lubricant composition according to claim 1. 9. The water-soluble fatty acid alkali salt has 8 carbon atoms.
1 to 22 saturated or unsaturated fatty acids, ether carboxylic acids having alkyl groups of these fatty acids, or ethylene oxide-added ether carboxylic acids having alkyl groups of these fatty acids, sodium salt, potassium salt, ammonium salt or alkanolamine salt, respectively. The lubricant composition of claim 1, which is of one or more species. 10. The lubricant composition according to claim 9, wherein the saturated or unsaturated fatty acid having 8 to 22 carbon atoms in claim 9 is coconut oil fatty acid, lauric acid, oleic acid or tallow fatty acid.