JPH07112776A - Aerosol container - Google Patents

Abstract

PURPOSE:To provide an aerosol container which has formed on its inner surface the coating having a high hardness and indicating not only an excellent adhesiveness to metal, shock resistance, water resistance and solvent resistance but also an excellent appearance and a persistent adhesiveness to metal even after heat sterilization and which is thus suitable for use in holding aerosol articles such as food, drink, cosmetics and medicines. CONSTITUTION:The inner surface of an aerosol container is coated with a coating resin composition (C) consisting of 40-97wt.% aromatic epoxy resin (A) and 3-60wt.% aromatic hydrocarbon formaldehyde resin modified aromatic epoxy resin (B).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an aerosol container. More specifically, the coating film formed on the inner surface exhibits excellent adhesion to metals, impact resistance, water resistance, solvent resistance, etc., and is, for example, an aerosol containing foods, beverages, cosmetics, pharmaceuticals, etc. as contents. The present invention relates to an aerosol container that can be suitably used for products.

[0002]

2. Description of the Related Art Conventionally, metals such as aluminum, tinplate, and tin-free steel have been used as materials for aerosol containers. The inner surface of such aerosol containers is usually coated with a coating film to prevent corrosion. Are formed.

Epoxy-phenol resin type, epoxy-acrylic resin type and epoxy-amino resin type paints are usually used to obtain the above-mentioned coating film. When these paints are used, Since there is a problem that the formed coating film has insufficient adhesion to metal, impact resistance, water resistance, solvent resistance, etc., development of an aerosol container in which these problems have been solved has been awaited. ing.

[0004]

Therefore, in view of the above-mentioned prior art, the inventors of the present invention have found that the coating film formed on the inner surface has a water-soluble resin present therein even after the heat sterilization treatment. As a result of intensive research to obtain an aerosol container that exhibits excellent adhesion to metals, impact resistance, water resistance, solvent resistance, etc., with almost no elution of the components, aromatic epoxy resin was used for aromatic carbonization. It was found that such an aerosol container can be obtained when a resin composition containing a hydrogen formaldehyde resin-modified aromatic epoxy resin is used, and the present invention has been completed.

[0005]

That is, the present invention comprises 40 to 97% by weight of an aromatic epoxy resin (A) and 3 to 60% by weight of an aromatic hydrocarbon formaldehyde resin-modified aromatic epoxy resin (B). The present invention relates to an aerosol container obtained by applying the coating resin composition (C) onto the inner surface.

[0006]

OPERATION AND EXAMPLES As described above, the aerosol container of the present invention has an aromatic epoxy resin (A) of 40 to 97.
A coating resin composition (C) comprising 3% to 60% by weight of an aromatic hydrocarbon formaldehyde resin-modified aromatic epoxy resin (B) is applied to the inner surface.

Examples of the aromatic epoxy resin (A) (hereinafter referred to as resin (A)) used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and fatty acid modified epoxy resin. Examples thereof include phenolic compound-modified epoxy resins, and among these, 1.1 to 2 epoxy groups are averaged in one molecule and the number average molecular weight is 20.
It is preferably 00 or more, especially 3000 or more.

Representative examples of the resin (A) include, for example, Epicoat 152, Epicoat 154, Epicoat 1
007, Epicoat 1009, Epicoat 1010, Epicoat 100L (these are trade names of Shell Kagaku Co., Ltd.) and the like, and these can be used alone or in combination of two or more kinds.

The aromatic hydrocarbon formaldehyde resin-modified aromatic epoxy resin (B) (hereinafter referred to as resin (B)) used in the present invention is, for example, an aromatic hydrocarbon formaldehyde resin (hereinafter referred to as resin (B) -1). And an epoxy resin (hereinafter referred to as resin (B) -2) are dissolved in a mixed solvent of, for example, diacetone alcohol, butyl cellosolve, xylene, etc.
It can be obtained by reacting at a temperature of about 0 to 170 ° C. for about 3 to 6 hours.

Examples of the resin (B) -1 include aromatic hydrocarbons such as toluene, xylene, mesitylene, durene, naphthalene, and a mixture of various alkylbenzenes, and formaldehyde in the presence of an acid catalyst such as sulfuric acid. It is intended to be E by reacting an aromatic hydrocarbon nucleus methylene bond (-CH ₂ -), methylene ether bond _{(-CH 2 -O-CH 2 -} ), acetal bond (-CH ₂ - (OCH _{2) n} -O-CH ₂ -, _n is 1 to
Bound by an integer of about 3), and a small amount of methylol group (—CH ₂ OH) and methoxy group (—CH ₂
OCH ₃ ) having a structure having a number average molecular weight of 250 to 900 and an oxygen content of 5 to 15% by weight, which is a liquid to semi-solid pale yellow resin and is usually a toluene resin, a xylene resin, a mesitylene resin. , Durene resin, naphthalene resin, alkylbenzene resin (also called AB resin)
There is a resin called.

Examples of the resin (B) -2 include the bisphenol A type epoxy resin, the bisphenol F type epoxy resin, the novolac type epoxy resin, the fatty acid modified epoxy resin and the phenol compound modified epoxy resin. Among these, those having an average of 1.1 to 2 epoxy groups in one molecule and having a number average molecular weight of 2000 or more, particularly 3000 or more are preferable.

A typical example of the resin (B) -2 is Epicoat 1 exemplified as the resin (A).
52, Epicoat 154, Epicoat 1007, Epicoat 1009, Epicoat 1010, Epicoat 100
L and the like can be used, and these can be used alone or in combination of two or more.

Resin (B) used in producing the resin (B)
-1 and the resin (B) -2 compounding ratio (resin (B) -1 /
The resin (B) -2) has a weight ratio of 20/80 / to 80/2.
0, especially 40/60 to 60/40 is preferable. When the blending ratio of the resin (B) -1 is less than the lower limit value, the adhesiveness to metal and corrosion resistance of the coating film formed using the obtained coating resin composition (C) are excellent. The effect of improving properties and the like tends to be insufficient, and when the amount exceeds the upper limit, gelation tends to occur during the reaction.

Examples of the solvent used for producing the resin (B) include ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, amyl alcohol, isoamyl alcohol, sec-amyl alcohol, n-. Alcohols such as hexanol and diacetone alcohol; glycol ethers such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, methyl carbitol and ethyl carbitol; glycol ether acetates such as methyl cellosolve acetate and ethyl cellosolve acetate; toluene, Examples thereof include aromatic hydrocarbons such as xylene and mesitylene, and these can be used alone or in admixture of two or more.

The charging ratio (mixture / solvent) of the mixture of the resin (B) -1 and the resin (B) -2 and the solvent is not particularly limited, but in consideration of the viscosity of the resin (B) to be obtained and the like, the weight thereof is 50/50 to 70/30, 55 /
It is preferably 45 to 65/35.

Examples of the acid catalyst used for producing the resin (B) include organic sulfonic acids such as p-toluenesulfonic acid and m-xylenesulfonic acid, metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, An acid formed by hydration of diphosphorus pentoxide such as tetraphosphoric acid can be mentioned.

The acid catalyst is used in an amount of 0.05 of the reaction product.
It is preferably ˜2% by weight, and particularly preferably about 0.5% by weight in consideration of reaction time and resin characteristics.

The coating resin composition (C) (hereinafter referred to as composition (C)) used in the present invention is, for example, the above resin (A) and resin (B) are uniformly mixed and stirred by using a stirrer or the like. The resin (A) and the resin (B) are mixed at a ratio of 40
-97 wt% and resin (B) 3-60 wt%, preferably resin (A) 60-97 wt% and resin (B)
Is 3 to 40% by weight. When the compounding ratio of the resin (B) is less than the lower limit value, the effect of improving the adhesion to metal and the corrosion resistance of the coating film formed by using the obtained composition (C). Becomes insufficient, and when it is more than the above upper limit, the coating film becomes too hard, and conversely the workability deteriorates.

The composition (C) can be heat-cured without using a curing agent. When the composition (C) is cured, the curing agent (D) may be, for example, a phenol resin, an amino resin, an acrylic resin or phosphoric acid. When an acidic phosphoric acid ester or the like is appropriately blended and used, the coating properties such as adhesion to metal, water resistance and solvent resistance can be further improved.

Examples of the phenol resin include phenol resole resin, alkyl etherified phenol resole resin, alkylphenol resole resin, and bisphenol A resole resin. These can be used alone or in admixture of two or more kinds. .

Typical examples of the above-mentioned phenol resin include, for example, METHYLON 75108, METHYLON 75121 (above, product name of General Electric Co., USA), and Hitanol (HI).
TANOL) 4010, HITANOL
4020 (above, product name of Hitachi Chemical Co., Ltd.) and the like.

The amount of the phenolic resin compounded is 5 to 50 parts with respect to 100 parts (parts by weight, the same applies hereinafter) of the composition (C).
It is preferably 7 to 40 parts, especially 7 to 40 parts. When the amount of the phenolic resin is less than 5 parts, the effect of improving the adhesion to metal and the corrosion resistance of the coating film formed by using the obtained composition (C) is too great. If it exceeds 50 parts, the coating film tends to become too hard and the workability tends to deteriorate.

Examples of the amino resins include alkyl etherified urea resins, alkyl etherified melamine resins, and alkyl etherified guanamine resins, which may be used alone or in admixture of two or more.

Typical examples of the amino resin include Sumimar M40S (trade name, manufactured by Sumitomo Chemical Co., Ltd.), Super Beckamine L-820-60 (trade name, manufactured by Dainippon Ink and Chemicals Co., Ltd.). , Cymel 1123,
Cymel 303 (above, product name of Mitsui Cyanamid Co., Ltd.) and the like.

The amount of the amino resin compounded is the composition (C).
It is preferably 5 to 50 parts, especially 7 to 40 parts per 100 parts. When the amount of the amino resin compounded is less than 5 parts, the effect of improving the adhesion to metal and the corrosion resistance of the coating film formed using the obtained composition (C) is too great. Tend to disappear,
On the other hand, if the amount is more than 50 parts, the coating film tends to be too hard and the workability tends to decrease.

Typical examples of the acrylic resin include 2-hydroxyethyl methacrylate-containing copolymers such as copolymers of acrylic acid, 2-hydroxyethyl methacrylate, styrene, butyl acrylate and azobisisobutyronitrile. Can be given.

The amount of the acrylic resin compounded is 5 to 50 parts per 100 parts of the composition (C), especially 7 to 4 parts.
It is preferably 0 part. If the amount of the acrylic resin compounded is less than 5 parts, the effect of improving the adhesion to the metal exhibited by the coating film formed using the obtained composition (C) tends to be insufficient. If it is more than 50 parts, the corrosion resistance tends to decrease.

Typical examples of the phosphoric acid include metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, tetraphosphoric acid, and other acids formed by hydration of diphosphorus pentoxide. As a typical example of the phosphoric acid ester,
Examples thereof include monobutyl phosphate ester, dibutyl phosphate ester, monohexyl phosphate ester, dihexyl phosphate ester, monooctyl phosphate ester, dioctyl phosphate ester and the like. These may be used alone or in combination of two or more. it can. Among the phosphoric acids, orthophosphoric acid is particularly preferable.

The compounding amount of at least one selected from phosphoric acid and acidic phosphoric acid ester is 10
It is preferably 0.01 to 5 parts, especially 0.1 to 2 parts with respect to 0 part. The compounding amount of at least one selected from such phosphoric acid and acidic phosphoric acid ester is 0.0
When it is less than 1 part, the effect of accelerating the curing speed tends not to be sufficiently exhibited, and when it is more than 5 parts, the coating composition formed by using the obtained composition (C). The film tends to become too hard and the workability tends to decrease.

The phosphoric acid and the acidic phosphoric acid ester act not only as a curing agent but also as a curing accelerator.

In addition to the curing agent (D), additives such as pigments, leveling agents, defoaming agents, and lubricants are added to the composition (C) in an appropriate amount. You can also do it.

The aerosol container of the present invention can be produced by applying the composition (C) to the inner surface of the container by means such as roll coating, spray coating or brush coating.

The material for the aerosol container of the present invention is not particularly limited as long as it is one normally used for aerosol products, and examples thereof include metals such as aluminum, tinplate and tin-free steel.

The composition (C) may be, for example, 5 to 5.
30 to 30 minutes from baking at 150-200 ℃
It can be cured under a wide range of baking conditions up to a high temperature for a short time of about 200 to 300 ° C. for about 2 to 2 minutes. The amount of the composition (C) applied to the inner surface of the aerosol container of the present invention is such that the dry film thickness of the formed coating film is 3
It is preferable to adjust the thickness to about 10 μm, especially about 4 to 6 μm.

Next, the aerosol container of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Production Example 1 (Preparation of Resin (B)) Nicanol H (manufactured by Mitsubishi Gas Chemical Co., Inc., xylene) was placed in a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas blowing tube. Resin, trade name) 500 g, Epikote 1007 500 g, xylene 215 g, diacetone alcohol 215 g and ethyl cellosolve 10
8 g was charged, the temperature was raised to 100 ° C., and the mixture was uniformly dissolved with slow stirring. Then, 7 g of p-toluenesulfonic acid was added, the temperature was raised to 130 ° C., and the reaction was carried out for 3 hours to obtain a resin (B ₁ ).

Production Example 2 (Preparation of Resin (A) Solution) In a four-necked flask equipped with a thermometer, a stirrer and a nitrogen gas blowing tube, 500 g of Epicoat 1007, 215 g of xylene, 215 g of diacetone alcohol and 108 g of ethyl cellosolve were placed. Was charged, the temperature was raised to 100 ° C., and the resin (A ₁ ) solution was obtained by uniformly dissolving the mixture with slow stirring.

Production Example 3 (Preparation of Acrylic Resin Solution) 100 parts of n-butanol was charged into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas blowing tube, and kept at 105 ° C. Acrylic acid 10 parts, 2-hydroxyethyl methacrylate 20 parts, styrene 40 parts, butyl acrylate 30 parts and azobisisobutyronitrile 3 are introduced from a dropping tank while introducing a base gas and stirring.
Part of the mixture was added dropwise over 3 hours.

After that, the reaction was carried out at 105 ° C. for 1 hour to obtain an acrylic resin solution having an acid value of 70 and a number average molecular weight of 1,000.

[0040] Examples 1-5 Resin (A ₁₎ 80 parts of the resin (B ₁₎ 20 parts of a curing agent shown in Table 1 (D) were uniformly mixed using a stirrer, the composition (C) I got it. This composition (C) was applied to the inner surface of an aluminum container using a spray coater to give a dry film thickness of about 5 μm.
After coating so as to have m, a coating film was formed by baking at 260 ° C. for 60 seconds to obtain an aerosol container.

The test on the physical properties of the formed coating film was carried out using a test piece prepared by forming a coating film on the same aluminum plate as the aerosol container in the same manner as described above.
The procedure was as follows. The results are shown in Table 1.

(A) Gel Fraction The test piece was cut into 10 cm × 10 cm, and the weight W ₁ (g)
Was measured. Then, methyl ethyl ketone / test piece = 100 ml / 100 cm ² was added to a beaker and heated until reflux, and after the reflux started, the test piece was placed and extracted under reflux of methyl ethyl ketone for 2 hours. After that, the test piece was taken out from the beaker, dried at 150 ° C. for 30 minutes, cooled to room temperature, and weighed W
(G) was measured.

The coating film of the test piece was peeled off with a mixed solvent of methyl ethyl ketone / cyclohexanone = 50/5 (weight ratio), dried at 150 ° C. for 30 minutes, cooled to room temperature, and the weight W ₂ (g) was measured. .

From these values, the gel fraction (% by weight) was calculated according to the following formula.

Gel fraction (wt%) = [((W ₁ -W)-
_{(W 1 -W 2)) /} (W 1 -W)] × 100 = [(W 2
_{-W) / (W 1 -W)} ] × 100 ( b) to observe the surface of the coating film appearance test piece was visually evaluated according to the following evaluation criteria.

(Evaluation Criteria) A: No abnormalities are recognized. B: A slight tinge or blurring is observed. C: Some slight scratches and blurring are observed. D: Tightness and gloss are recognized. E: Ijirushi Ichijimi and gloss are blurred.

(C) Pencil Hardness The pencil hardness was determined according to the method specified in JIS K-5400.

(D) Impact resistance The height of the weight (cm) in which the coating film was cracked or peeled by impact processing from the front and back of the test piece with a weight of 3/8 "and a load of 500 g Was measured.

(E) Retort resistance The test piece was immersed in deionized water and placed in an autoclave for 1 day.
Treatment was carried out at 25 ° C. for 30 minutes, the whitening state of the coating film was visually observed, and evaluated according to the following evaluation criteria.

(Evaluation Criteria) A: No whitening and no change. B: A little whitened. C: Whitening is remarkable.

Further, the coating film of the test piece which has been subjected to the above treatment is cut with a cutter until it reaches the base material (metal) to form gouged stitches (1 mm interval, vertical 12 mm × horizontal 12 mm). Adhere the adhesive tape (cellophane adhesive tape) on the surface and pull it away in a direction of 180 degrees,
The state of adhesion of the coating film to the substrate was visually observed and evaluated according to the following evaluation criteria.

(Evaluation Criteria) A: All the crevices of the coating film adhere. B: Almost half of the streaks of the coating film are attached. C: Almost no creases on the coating film adhered.

Comparative Examples 1 to 5 80 parts of resin (B ₁ ) and the curing agent (D) shown in Table 1 were uniformly mixed using a stirrer to obtain compositions. Using this composition, aerosol containers were obtained in the same manner as in Examples 1-5.

Tests on the physical properties of the formed coating films were conducted in the same manner as in Examples 1-5. The results are shown in Table 1.

The curing agent (D) in Table 1 is as follows.

D ₁ : Hitanol 4020, phenol resin D ₂ : Superbeckamine L-820-60, amino resin D ₃ : Acrylic resin obtained in Production Example 3 D ₄ : 10% orthophosphoric acid

[0057]

[Table 1]

From the results shown in Table 1, aerosol containers obtained by using the composition (C) of Examples 1 to 5 were formed compared with those obtained in Comparative Examples 1 to 5. The coating film has a high gel fraction, high hardness, excellent appearance without scratches and blurring on the surface, and has excellent impact resistance, appearance after heat sterilization and adhesion to the substrate. It turns out to be a thing.

[0059]

EFFECT OF THE INVENTION The aerosol container of the present invention has a coating film formed on the inner surface having a high hardness, and exhibits excellent adhesion to metal, impact resistance, water resistance, solvent resistance and the like. Since, even after heat sterilization treatment, it also has an excellent appearance and adhesion to metal, it can be suitably used for aerosol products containing foods, beverages, cosmetics, pharmaceuticals, etc. Play.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazutaka Yamagishi 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Sanryo Gas Chemical Co., Ltd. Plastics Center

Claims (5)

[Claims] 1. Aromatic epoxy resin (A) 40 to 97
An aerosol container comprising an inner surface coated with a coating resin composition (C) comprising 3% to 60% by weight of an aromatic hydrocarbon formaldehyde resin-modified aromatic epoxy resin (B). 2. The coating resin composition (C) contains 5 to 50 parts by weight of a phenol resin as a curing agent (D) with respect to 100 parts by weight of the coating resin composition (C). 1. The aerosol container according to 1. 3. The coating resin composition (C) contains 5 to 50 parts by weight of an amino resin as a curing agent (D) with respect to 100 parts by weight of the coating resin composition (C). 1. The aerosol container according to 1. 4. The coating resin composition (C) contains 5 to 50 parts by weight of an acrylic resin as a curing agent (D) with respect to 100 parts by weight of the coating resin composition (C). 1. The aerosol container according to 1. 5. The coating resin composition (C) comprises at least one selected from phosphoric acid and acidic phosphoric acid ester as a curing agent (D) based on 100 parts by weight of the coating resin composition (C). The aerosol container according to claim 1, which contains 0.01 to 5 parts by weight.