JP2001278326A - Can lid having sealing compound and metal can using the can lid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a can lid having sealing compound and a metal can made of aluminum for drinks or the like using the said can lid which do not spoil sealability and improve the finess at the external appearance while being free from exudation of compound to the outside of a seamed part of the can by using a sealing compound which is less liable to vary in fluidity under the circumstances where the temperature varies. SOLUTION: A sealing compound made up by dissolving or dispersing a thermoplastic elastomer, a sticking agent and a filling material into a solvent is applied to the can lid having sealing compound. A styrene thermoplastic elastomer is used to form the thermoplastic elastomer. The styrene is included in the thermoplastic elastomer in the ratio of 5 to 50 wt.%. The metal can is made up by putting the can lid having sealing compound on an opening thereof and by seaming the periphery of the can lid and the periphery of the opening at a trunk part of the can together.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can lid with a sealing compound and a metal can using the same.

[0002]

2. Description of the Related Art Conventionally, in double winding of metal cans such as beverage cans, a rubber-like substance called a sealing compound previously lined on a can lid fills a gap inside the winding can to maintain the seal. Have been.

[0003] As the above-mentioned sealing compound, a so-called solvent-type sealing compound in which a synthetic rubber, a pressure-sensitive adhesive, a filler and various additives are dissolved or dispersed in a volatile organic solvent to form a liquid is already known. Solvent-type sealing compounds are widely used in beverage cans and the like because the solvent can be removed by air drying after application and no drying equipment is required.

Here, in the solvent-type sealing compound, the synthetic rubber, which is the main component, is limited to a solvent-soluble one, and most of the uncured styrene-butadiene rubber is used.

[0005]

However, in a conventional solvent-type sealing compound applied to a can lid,
Since the rubber is significantly softened as the temperature rises, the fluidity of the sealing compound varies greatly depending on the operating temperature of the sealing compound. That is, when a sealing compound optimized for use at a low temperature is used at a high temperature, its fluidity becomes too large. As a result, the sealing performance of the metal can is impaired,
There is a problem that the compound oozes out of the tightened portion and impairs the appearance.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to use a sealing compound having a small change in fluidity even with a change in use temperature, without impairing the sealing performance of a metal can and at the same time. An object of the present invention is to provide a can lid with a sealing compound and a metal can using the same, which can improve the appearance of the metal can without exuding the compound to the outside of the fastening portion.

[0007]

According to a first aspect of the present invention, there is provided a can lid with a sealing compound, wherein a sealing compound mainly composed of a thermoplastic elastomer is provided on a peripheral edge portion for winding. Is applied.

In the above, the sealing compound comprises a thermoplastic elastomer, an adhesive and a filler, and if necessary, additives such as an antioxidant and a pigment.
It is dissolved or dispersed in a solvent.

The thermoplastic elastomer is a styrene-based thermoplastic elastomer composed of a styrene- (hydrogenated) butadiene-styrene block copolymer or a styrene- (hydrogenated) isoprene-styrene block copolymer. Is preferred.

[0010] The ratio of styrene in the styrene-based thermoplastic elastomer is preferably 5 to 50% by weight.

The metal can according to claim 5 of the present invention uses a can lid with a sealing compound in which a sealing compound containing a thermoplastic elastomer as a main component is applied to a peripheral portion for winding, and the can with the sealing compound is used. A lid is placed over the opening of the can body, and the periphery of the can lid and the periphery of the can body opening are tightly wound.

[0012]

Next, an embodiment of the present invention will be described.

[0013] In the can lid with a sealing compound according to the present invention, a sealing compound containing a thermoplastic elastomer as a main component is applied to a peripheral portion for winding.

Here, the can lid is usually made of aluminum (including an aluminum alloy).

[0015] As a can filled with beverages such as fruit juice or beer, foods such as meat storage, fish meat or vegetables, a three-piece can in which a can lid is put on a top and a bottom of a steel can body and tightly wound, respectively, At the top of an aluminum can body having a bottom wall, two types of two-piece cans obtained by winding a can lid are used. The can lid with a sealing compound of the present invention is applied to any of these cans. Things. The can lid on the top of the can body is usually provided with an easy-open mechanism.

The above-mentioned sealing compound is obtained by dissolving or dispersing a thermoplastic elastomer, a pressure-sensitive adhesive and a filler, and if necessary, additives such as an antioxidant and a pigment in a solvent.

Here, as the thermoplastic elastomer,
Styrene- (hydrogenated) butadiene-styrene block copolymer or styrene- (hydrogenated) isoprene-
It is preferably a styrene-based thermoplastic elastomer composed of a styrene-block copolymer. The ratio of styrene in the styrene thermoplastic elastomer is 5%.
Preferably it is 〜50% by weight.

The styrene-based thermoplastic elastomer as described above has a styrene block having a softening point below its softening point.
Due to physical crosslinking, it exhibits properties similar to vulcanized rubber and is soluble in solvents.

The pressure-sensitive adhesive is used for imparting adhesiveness of the sealing compound to the can lid and improving the sealing property. Examples of such pressure-sensitive adhesive include terpene resin, rosin resin, and other thermoplastic elastomers. Known resins having excellent solubility can be used.

The amount of the adhesive is preferably 10 to 200 parts by weight based on the thermoplastic elastomer. Here, if the amount of the adhesive is less than 10 parts by weight with respect to the thermoplastic elastomer, the adhesion of the sealing compound to the can lid is insufficient, and if it exceeds 200 parts by weight,
It is not preferable because rubber elasticity decreases.

The filler is used for adjusting the hardness of the sealing compound, increasing the amount of the sealing compound, and adjusting the drying speed. Examples of the filler include silica, clay, talc, alumina, and other known fillers. Inorganic materials can be used.

The solvent facilitates application to the can lid by dissolving or dispersing the components of the sealing compound. Examples of the solvent include alkanes, cycloalkanes, ketones, and mixtures thereof. Can be used. The solvent affects the viscosity and the drying speed of the sealing compound when it is applied.

Further, as the antioxidant added as required, known antioxidants such as phenol derivatives such as dibutylhydroxytoluene (BHT) and amines and derivatives thereof can be used.

As the pigment, titanium white, carbon black, red iron, aluminum powder and other known pigments can be used.

The amount of the constituent components in the sealing compound is, for example, from 10 to 3 of thermoplastic elastomer.
0% by weight, 3 to 40% by weight of an adhesive, 2 to 20% by weight of a filler, and 40 to 85% by weight of a solvent. If necessary, 0.1 to 1.0% by weight of an antioxidant, and a pigment. 0.
Add additives such as 1-10% by weight.

Further, the metal can according to the present invention uses a can lid with a sealing compound in which a sealing compound containing a thermoplastic elastomer as a main component is applied to a peripheral portion for winding, and the can lid with the sealing compound is In the case of a three-piece can, the top part and the bottom part of the steel can body are respectively covered, and the can lid peripheral part and the can body opening peripheral part are tightly wound. In the case of a two-piece can, The top of an aluminum can body having a bottom wall is covered with a can lid, and the can lid periphery and the can body opening periphery are tightly wound.

[0027]

Next, an embodiment of the present invention will be described.

Examples 1 to 3 As the thermoplastic elastomer, styrene-butadiene-
Styrene block copolymer (SBS) and styrene-isoprene-styrene block copolymer (SI
S), terpene resin as an adhesive, silica as a filler, dibutylhydroxytoluene (B
HT) and cyclohexane and acetone as solvents, each of which was blended in the proportions shown in Table 1 and sufficiently stirred to prepare three types of sealing compounds for use in the can lid of the present invention.

Then, when these sealing compounds were applied so as to fill an annular groove provided on the peripheral edge portion of the aluminum can lid for winding, the applicability was good.

When these three kinds of can lids with a sealing compound were put on the can body opening of a two-piece aluminum can and filled with a cold pack and a hot pack, no leakage of the contents occurred in any case. And had good sealing performance.

Further, the filling can was subjected to a retort treatment at 116 ° C. for 23 minutes, and the occurrence rate of seepage of the sealing compound was measured.

Further, the loss coefficient (loss tangent) (ta) in the dynamic viscoelasticity of these three types of sealing compounds is
nδ) was measured at room temperature and 90 ° C., respectively, and the obtained results are summarized in Table 1 below.

Comparative Example 1 For comparison, a can lid with a sealing compound was prepared by a conventional sealing compound using styrene-butadiene rubber (SBR) as a main component of the sealing compound. As in the case of the example, the two-piece aluminum can was covered with the can body opening and filled with a cold pack and a hot pack. Further, the filled can was subjected to retort treatment, and the occurrence rate of seepage of the sealing compound was measured. Further, for the conventional sealing compound, the loss coefficient (ta) in the dynamic viscoelasticity was the same as in the above-described embodiment.
nδ) was measured, and the obtained results are shown in Table 1.

Comparative Examples 2 and 3 For comparison, styrene-butadiene-styrene block copolymer (SBS) was used as a thermoplastic elastomer.
But the ratio of styrene in the styrene-based thermoplastic elastomer is different from those in Examples 1 and 2 above.
Seed sealing compounds were prepared. Using the sealing compound for comparison, a can lid with a sealing compound was prepared, and this can lid was placed over the opening of the can body of an aluminum two-piece can in the same manner as in the above-described example, and a cold pack and a hot pack were prepared. Filling was performed. Further, the filled can was subjected to retort treatment, and the occurrence rate of seepage of the sealing compound was measured. Further, for the conventional sealing compound, the loss factor (tan) in the dynamic viscoelasticity was the same as in the above-described embodiment.
δ) was measured, and the obtained results are shown in Table 1.

The above Examples 1 to 3 and Comparative Examples 1 to
Regarding all the filling cans of No. 3, the cross-sectional shapes of the tightened portions of the filling cans were observed.

Here, ◎: good, ○: slightly unsuitable shape but no leakage, ×: possible leakage, evaluated on a three-point scale.

Further, all the filling cans were comprehensively evaluated, and the obtained results are shown in Table 1.

The overall evaluation was evaluated in four steps: ◎: good for practical use, ：: practically usable, Δ: slightly difficult for practical use, ×: unsuitable for practical use.

[0039]

[Table 1] As is clear from the results in Table 1 above, according to the can lids with the sealing compound of the present invention of Examples 1 to 3, the bleeding rate of the sealing compound was lower than that of the conventional product (Comparative Example 1) and Comparative Example 2. Had also declined significantly.

The loss coefficient (ta) in dynamic viscoelasticity
According to the can lid with the sealing compound of the present invention (Examples 1 to 3), the change in the measured values at room temperature and 90 ° C. was the same as that of the conventional product (Comparative Example 1) and Comparative Examples 2 and 3. It was confirmed that the change was smaller than the change in the value.

FIGS. 1 and 2 show measured values of the loss coefficient (tan δ) in dynamic viscoelasticity at room temperature and 90 ° C. of the products of the present invention of Examples 1 and 2 and the conventional product of Comparative Example 1. Was graphed.

As shown in FIG. 1, at room temperature, the loss coefficient (tan δ) in dynamic viscoelasticity shows almost the same results. However, as shown in FIG. And 2, the can lid with the sealing compound of the present invention is smaller than the conventional can of Comparative Example 1 at room temperature and 90 ° C.
It is confirmed that the change in the measured value of the loss coefficient (tan δ) at ° C. is small.

[0043]

As described above, the can lid with a sealing compound according to the first aspect of the present invention has a sealing compound containing a thermoplastic elastomer as a main component applied to a peripheral portion for winding. According to the present invention, by using a sealing compound having a small change in fluidity even with a change in use temperature, without impairing the sealing performance of the metal can, and without exuding the compound to the outside of the tightened portion, the metal can This has the effect of improving the beauty of the camera.

According to a fifth aspect of the present invention, there is provided a metal can having a sealing compound having a sealing compound having a thermoplastic elastomer as a main component applied to a peripheral portion for winding, the can having a sealing compound. Since the lid is placed over the opening of the can body and the peripheral edge of the can lid and the peripheral edge of the can body opening are tightly wound, the lid has a sufficient sealing property to prevent leakage of the contents. It can be reliably prevented, can be used as a beverage can or the like, and has an effect that the compound does not exude to the outside of the tightened portion between the can lid and the can body, and the aesthetic appearance is excellent.

[Brief description of the drawings]

FIG. 1. Loss factor (t) in dynamic viscoelasticity at room temperature
9 is a graph showing measured values of an δ).

FIG. 2 is a graph showing measured values of loss coefficient (tan δ) in dynamic viscoelasticity at 90 ° C.

Claims (5)

[Claims] 1. A can lid with a sealing compound, characterized in that a sealing compound containing a thermoplastic elastomer as a main component is applied to a peripheral portion for winding. 2. The can lid with a sealing compound according to claim 1, wherein the sealing compound is obtained by dissolving or dispersing a thermoplastic elastomer, an adhesive and a filler in a solvent. 3. The method of claim 1, wherein the thermoplastic elastomer is styrene-
(Hydrogenated) butadiene-styrene block copolymer or styrene- (hydrogenated) isoprene-styrene.
The can lid with a sealing compound according to claim 1 or 2, which is a styrene-based thermoplastic elastomer made of a block copolymer. 4. The can lid with a sealing compound according to claim 3, wherein the proportion of styrene in the thermoplastic elastomer is 5 to 50% by weight. 5. The can lid with the sealing compound according to claim 1, wherein the can lid is covered over an opening of the can body, and the can lid periphery and the can body opening periphery are tightly wound. Metal cans.