JPH09302317A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition high in adhering performance, also good in heat stability and used for a hygienic material such as a paper diaper by mixing a synthetic rubber-based component, a resin component imparting an adhering property, a plasticizing oil component and a stabilizer containing a specific substance in each specific ratio. SOLUTION: This adhesive composition contains (A) 100 pts.wt. synthetic rubber-based component, (B) 90-400 pt.wt. resin component imparting an adhesive property, (C) 10-200 plasticizing oil component and (D) (i) 0.1-15 pt.wt. stabilizer component consisting of a mercaptomethylphenol of formula I [R<1> , R<2> are each independently a 1-12C alkyl, the formula: CH2 -SR<3> (R<3> is a 6-18C alkyl, phenyl or benzyl); R<4> 's are each independently H or methyl, provided that R<4> 's bound to the same ring are not simultaneously methyl; (n) is 0, 1] and (ii) 0.2-30 pt.wt. stabilizer consisting of a 3-22C epoxidized fatty acid or an alkyl ester of the same acid with a 1-18C alcohol. Further, the weight ratio of the components (i) to (ii) is preferably (1:3)-(1:7).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an adhesive composition used for assembling sanitary materials such as disposable diapers and sanitary napkins. More specifically, the present invention relates to an adhesive composition exhibiting high adhesive performance and good thermal stability. It is about things.

[0002]

2. Description of the Related Art Recently, as an adhesive composition used for assembling sanitary materials such as disposable diapers and sanitary napkins, styrene-butadiene-styrene block copolymer (SBS), styrene-isobrene- have been used as synthetic rubber components. Styrene block copolymer (SIS) (JP-A-4-351689)
(See Japanese Patent Publication) and the like are known. Further, for the purpose of improving thermal stability, a hydrogenated product of the above rubber component,
For example, styrene-ethylene-butylene-styrene block copolymer (SEBS) (see Japanese Patent Publication No. 7-57868), styrene-ethylene-propylene-styrene block copolymer (SEPS) (see Japanese Patent Publication No. 7-57867). And the like, and those to which a tackifying resin, a plasticizing oil, and a stabilizer component (such as an antioxidant) (see JP-A-5-320641) are further used for the above-mentioned applications.

However, in these adhesive compositions,
Synthetic rubber compounds or tackifying resin compounds having unsaturated double bonds, for example, as a synthetic rubber component, SI
S, SBS or their partially hydrogenated products, or those using unhydrogenated products, partially hydrogenated products, etc. as tackifying resin components, have a low manufacturing cost, but are thermally stable during manufacturing or during work. It has poor properties, and has the drawback that coloring, viscosity change, and generation of foreign matter are likely to occur. In addition, when SEBS or SEPS is used as a synthetic rubber component mainly for the purpose of improving thermal stability in applications where strong adhesion is required, there is a problem that the manufacturing cost becomes high.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive composition satisfying both the required adhesiveness and thermal stability at the same time in view of the above circumstances.

[0005]

The adhesive composition according to the present invention has been devised so as to achieve the above-mentioned object, and 90 parts by weight of the tackifying resin component are added to 100 parts by weight of the synthetic rubber component.
400 parts by weight, plasticizing oil component 10 to 200 parts by weight,
The following general formula (I)

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[Wherein R ¹ and R ² are independently of each other an alkyl group having 1 to 12 carbon atoms or the formula:
CH ₂ —SR ³ (R ³ represents an alkyl group having 6 to 18 carbon atoms, a phenyl group or a benzyl group) and R ⁴ independently of each other represent a hydrogen atom or a methyl group. However R ⁴ bound to the same ring not a methyl group simultaneously. n is 0 or 1. ] Stabilizer component consisting of mercaptomethylphenol
(a) Stable consisting of 0.1 to 15 parts by weight and an epoxidized fatty acid having 3 to 22 carbon atoms, or an alkyl ester of this epoxidized fatty acid with an alcohol having 1 to 18 carbon atoms. Agent component (b) 0.2 to 30
It contains a part by weight.

In a preferred embodiment of the present invention, the compounding ratio of the stabilizer component is preferably 0.3 parts of the stabilizer component (a).
10 to 10 parts by weight, and the stabilizer component (b) is 1.5 to 20 parts by weight. The weight ratio of the stabilizer component is preferably the stabilizer component (a): stabilizer component (b) = 1: 3 to 1: 7 in the blending ratio of the preferred embodiment.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the adhesive composition according to the present invention, the synthetic rubber-like component imparts tackiness. As the synthetic rubber component, for example, an unhydrogenated or partially hydrogenated synthetic rubber having an unsaturated double bond such as SBS or SIS is particularly preferable. Further, SEBS, SEPS, ethylene-vinyl acetate copolymer used in conventional adhesive compositions,
Ethylene copolymers such as ethylene-ethyl acrylate copolymer, polyolefin resins such as atactic polypropylene, isotactic polypropylene, propylene-1-butene-ethylene terpolymer and the like can also be used.

These synthetic rubber components may be used alone or in combination of two or more.

Further, a softening agent such as liquid polyisobutylene, liquid polybutene, liquid polyisoprene and the like may be added to the synthetic rubber component.

In the adhesive composition according to the present invention, if the blending ratio of the synthetic rubber component is too small, the resulting adhesive composition has a decrease in coating workability due to an increase in melt viscosity and a lack of initial adhesive strength. On the contrary, if the amount is too large, the cohesive force and low-temperature adhesiveness of the adhesive composition will be insufficient.

Examples of the tackifying resin component include rosin resin, modified rosin resin, terpene resin, modified terpene resin, aliphatic petroleum resin, aromatic petroleum resin,
Examples thereof include aliphatic-aromatic petroleum resins and styrene petroleum resins, which may be unhydrogenated or partially hydrogenated.

The mixing ratio of the tackifying resin component is 90 to 400 parts by weight, preferably 150 to 350 parts by weight, relative to 100 parts by weight of the synthetic rubber component.

If the blending ratio of the tackifying resin component is too small, the resulting adhesive composition will not exhibit the desired adhesive performance, and conversely if it is too large, the resulting adhesive composition will have low temperature adhesiveness. It is inferior and the flexibility is reduced.

As the plasticizing oil component, a usual paraffinic, naphthene-based, or aromatic plasticizing oil component is used, and these are blended alone or in combination of two or more.

The blending ratio of the plasticizing oil component is 10 to 200 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the synthetic rubber component.

If the blending ratio of the plasticizing oil component is too small, the obtained adhesive composition is inferior in low-temperature adhesiveness, and if it is too large, the adhesive composition lacks in high-temperature adhesiveness, paper diapers and sanitary products. Exudation of low molecular weight substances in the adhesive composition onto a napkin or the like occurs.

In the stabilizer component (a) composed of mercaptomethylphenol represented by the general formula (I), examples of the alkyl group represented by R ¹ and R ² include a methyl group, an ethyl group, a propyl group, Examples thereof include a butyl group, a hexyl group, an octyl group, an undecyl group and a dodecyl group, and branched isomer groups thereof. In the formulas represented by R ¹ and R ² : —CH ₂ —SR ³ , R ₃ is a phenyl group, a benzyl group, a hexyl group, an octyl group, a nonyl group, a decyl group, a tetradecyl group, an octadecyl group, or these. 6 to 1 like branched isomers of
Examples are those which are alkyl groups having 8 carbon atoms.

The proportion of the stabilizer component (a) is 0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the synthetic rubber component.

If the compounding ratio of the stabilizer component (a) is too small, the resulting adhesive composition is inferior in heat stability, and conversely if too much is contained, the adhesive composition emits a strong odor, so that the paper diaper or the physiological It is unsuitable for adhering napkins, etc.

Another stabilizer component (b) is a free epoxidized fatty acid having 3 to 22 carbon atoms, or this epoxidized fatty acid and an alcohol having 1 to 18 carbon atoms. It consists of an alkyl ester. Examples of the free epoxidized fatty acid include epoxidized oleic acid, epoxidized linoleic acid, epoxidized linolenic acid, epoxidized eucalic acid, epoxidized ricinoleic acid, and epoxidized brassic acid. The alcohol is a monohydric or polyhydric alcohol, such as methanol,
Butanol, lauryl alcohol, octyl alcohol, pentaerythritol, glycerol, ethylene glycol, propylene glycol, butylene glycol,
Examples include neopentyl glycol, mannitol and sorbitol. The polyhydric alcohol may be fully esterified or partially esterified. The stabilizer component (b) may also be an epoxidized higher fatty acid ester such as epoxidized cottonseed oil, castor oil, sunflower oil, olive oil, epoxidized animal oil, especially epoxidized soybean oil, flaxseed oil or mixtures thereof. .

The compounding ratio of the stabilizer component (b) is 0.2 to 35 parts by weight, preferably 1.5 to 20 parts by weight, based on 100 parts by weight of the synthetic rubber component.

If the compounding ratio of the stabilizer component (b) is too small, the resulting adhesive composition is inferior in heat stability, and conversely if it is too large, the adhesive composition emits a strong odor. It is unsuitable for adhering napkins, etc.

The weight ratio of the stabilizer component is preferably stabilizer component (a): stabilizer component (b) = 1: 3 to 1: 7, more preferably 1: 2.5 to 1: 5. is there. By setting the weight ratio of the stabilizer component in such a range, the thermal stability of the obtained adhesive composition can be particularly improved.

The adhesive composition of the present invention may contain various additives used in conventional adhesive compositions, in addition to the above essential components. Examples of such additives include stabilizers for improving heat resistance, oxidation resistance, and light resistance stability, and ultraviolet absorbers.

The adhesive composition of the present invention can be obtained, for example, by putting the above-mentioned components in a melt-stirring mixer and mixing them by heating.

[0027]

EXAMPLES In order to demonstrate the effect of the adhesive composition according to the present invention, some examples of the present invention and comparative examples to be compared therewith are shown.

Example 1 As a synthetic rubber component, 100 parts by weight of SBS block copolymer (Tafprene A) manufactured by Nippon Zeon Co., Ltd. was used as a tackifying resin component by a hydrogenated alicyclic saturated hydrocarbon resin (Arcon M-100) 275 parts by weight and 125 parts by weight of Idemitsu Kosan Co., Ltd. naphthenic mineral oil (Cielflex 371J) as a plasticizing oil component, respectively, and further, as a stabilizer component (a), mercaptomethyl manufactured by Ciba Geigy. 2.0 parts by weight of phenolic primary antioxidant (Irganox 1520D) and stabilizer component (b)
As an adhesive composition, 5.0 parts by weight of epoxidized soybean oil (Leoplast 39) manufactured by Ciba-Geigy Co., Ltd. were blended, and the blend was melt-kneaded to obtain an adhesive composition.

Example 2 The proportion of the stabilizer component (a) was changed to 0.5 parts by weight, and the proportion of the stabilizer component (b) was changed to 2.5 parts by weight. , Except that 2.0 parts by weight of a phenol-based heat-resistant processing stabilizer (Sumilyzer GM) manufactured by Sumitomo Chemical Co., Ltd. and 2.0 parts by weight of a phenol-based primary antioxidant (Irganox 1010) manufactured by Ciba-Geigy were blended. An adhesive composition was obtained in the same manner as in Example 1.

Comparative Examples 1 to 7 As other stabilizer components, a phenol-based heat-resistant processing stabilizer (Sumilyzer GM) manufactured by Sumitomo Chemical Co., Ltd., and a phenol-based primary antioxidant (IRGANOX 101 manufactured by Ciba-Geigy) were used.
0), bisphenol-based primary antioxidants (NS-5, NS-6) manufactured by Ouchi Shinko Co., Ltd., and phosphorus-based secondary antioxidants (Irgafos 168) manufactured by Ciba-Geigy Co., Ltd. were used in the respective mixing ratios shown in Table 1. An adhesive composition was obtained in the same manner as in Example 1 except for the above points.

Performance Test Each of the adhesive compositions obtained in Examples and Comparative Examples was used as a sample, and these samples were subjected to aging treatment at 180 ° C. for 2 days in a hot air circulation dryer, and then the Gardner color was measured. The presence or absence of the generation of foreign matter such as carbide was visually observed. The results are shown in Table 1.

[0032]

[Table 1]

In Table 1, stabilizer component (a) mercaptomethylphenol-based primary antioxidant: phenol-based primary antioxidant (IRGANOX 1520D, manufactured by Ciba Geigy) Stabilizer component (b) epoxidized soybean oil: Ciba Geigy Epoxidized soybean oil (Leoplast 39) and other stabilizer components Phenol-based heat-resistant processing stabilizer: Sumitomo Chemical Phenol-based heat-resistant processing stabilizer (Sumilyzer GM) Bisphenol-based primary antioxidant (1): Shin Ouchi Bisphenol-based primary antioxidant (NS-5) manufactured by bisphenol-based primary antioxidant (2): Ouchi Shinko Co., Ltd. bisphenol-based primary antioxidant (NS-6) Phosphorus-based secondary antioxidant: Ciba Geigy Phosphorus Secondary Antioxidant (Irgafos 168) Phenol Primary Antioxidant: Ciba Geigy Phenolic Primary Antioxidant ( (Irganox 1010)

Evaluation criteria for the generation of foreign matter: ○ → No foreign matter is found △ → Slight foreign matter is found × → Foreign matter is clearly generated

As is clear from Table 1, it is recognized that the adhesive compositions of Examples have excellent thermal stability.

[0036]

Since the adhesive composition according to the present invention contains a specific substance as a stabilizer component in a required ratio,
It exhibits good thermal stability.

In particular, S having an unsaturated double bond in the compound
This effect is remarkable when a BS-based or SIS-based synthetic rubber component or a tackifying resin component is used. Therefore, S
It is possible to provide an adhesive composition containing BS and SIS-based synthetic rubber components and satisfying the required adhesiveness and thermal stability at the same time.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C09J 193/04 JAK C09J 193/04 JAK

Claims (3)

[Claims] 1. To 100 parts by weight of a synthetic rubber component, 90 to 400 parts by weight of a tackifying resin component, 10 to 200 parts by weight of a plasticizing oil component, and the following general formula (I): [Wherein R ¹ and R ² are each independently of the other an alkyl group having 1 to 12 carbon atoms or a group of the formula: —CH ₂ —SR
³ (R ³ is an alkyl group having 6 to 18 carbon atoms,
Represents a phenyl group or a benzyl group. ), And R ⁴
Independently of each other means a hydrogen atom or a methyl group.
However R ⁴ bound to the same ring not a methyl group simultaneously. n is 0 or 1. ] Stabilizer component (a) consisting of mercaptomethylphenol represented by
Stabilizer component (b) 0. 15 parts by weight and an epoxidized fatty acid having 3 to 22 carbon atoms or an alkyl ester of this epoxidized fatty acid with an alcohol having 1 to 18 carbon atoms. An adhesive composition containing 2 to 30 parts by weight. 2. 0.3 to 10 parts by weight of the stabilizer component (a),
A stabilizer component (b) is contained in an amount of 1.5 to 20 parts by weight.
The adhesive composition as described in the above. 3. The adhesive composition according to claim 2, wherein the weight ratio of the stabilizer component (a) to the stabilizer component (b) is 1: 3 to 1: 7.