JPH0131530B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to resins based on α-methylstyrene, styrene and phenol as components, and to a process for their preparation.

Resins based on the above components are known in the art for various purposes. British Patent Specification No.
No. 1131163 discloses water-soluble resins obtained by the reaction of formaldehyde with a condensation product of phenol, optionally some cresol, and styrene or α-methylstyrene over a Friedel-Crafts catalyst. This intermediate condensation product converts styrene (or α-methylstyrene) into an excess of phenol, i.e. 0.1 to
It is prepared by reacting with 0.5 moles of styrene to form a phenolic resin containing from 10 to 30% by weight of styrene 64 to 90% by weight of phenol.

U.S. Patent No. 3,189,569 is approximately 65-80% by weight
of a vinyl aryl compound, about 20-35% by weight acrylonitrile, less than 1% by weight trisubstituted phenols, and optionally less than 1% by weight of an epoxidized compound.

U.S. Patent No. 2,558,812 is about 5-25 mol%
of phenols, about 25 to 45 mole percent aromatic hydrocarbons, and 50 to 60 mole percent conjugated aliphatic diene hydrocarbons such as butadiene, isoprene, or cyclopentadiene. French Patent Specification No. 7419993 (Registration No. 2232554) and corresponding US Patent Specification No. 1457356 are based on alpha-methylstyrene, styrene, phenol and 5-50% by weight of isobutene, with relatively low softening A resin is disclosed that produces a dot resin.

However, use in hot melt and pressure sensitive adhesives requires relatively high softening points, good compatibility with natural or synthetic elastomers, satisfactory peel strength, shear adhesion and tack.

The resin according to the present invention has a good combination of properties that satisfy the above requirements, and also has ethylene-
It also exhibits improved compatibility with vinyl acetate copolymers (EVA), atactic polypropylene (APP) and ethyl acrylate copolymers (EEA).

Certain resins useful in adhesives, especially hot melt pressure sensitive adhesives, have an α
- Methystyrene, based on a mixture of α-methylstyrene, styrene and phenol, consisting of 35-73% by weight of styrene and 2-15% by weight of phenol. These percentages total 100 or substantially
100, because technical grade ingredients may contain small amounts of impurities. For example, technical grade alpha-methylstyrene is typically over 98% pure, with impurities being aromatic solvents and styrene. Industrial grade styrene is typically 99
% purity, the main impurity is aromatic solvent. Certain technical grade products containing these starting materials along with non-polymerizable solvents may still be used to produce resins comprised of 98% or more of the above components.

In a preferred embodiment of this invention, the resin is
It is composed of 25-57% by weight alpha-methylstyrene, 40-72% styrene and 3-10% phenol.

Structural formula: (wherein R represents hydrogen or a C ₁ -C ₁₂ alkyl group, preferably a C ₆ -C ₁₀ alkyl group), styrene and phenol are in the form of technical grade compounds (purity of 95% or more). You can use it. Depending on their nature and reactivity, some of these impurities may be included in the resin. Resins containing a combination of phenols and C ₆ -C ₁₀ monoalkyl phenols, such as octylphenol, are desirable for adhesives. Unless large amounts of phenol and/or α-methylstyrene are used relative to styrene, the resins of this invention typically exhibit softening points (rings and balls according to ASTME 28) of about 70° to 120°C.
Compatibility with elastomers such as natural and synthetic rubbers is excellent, giving typical cloud points below 30° C. and producing clear mixtures. The average molecular weight of these resins ranges from about 400 to 2000 depending on the percentage of phenol present.

The resin according to the invention may be prepared in the presence of a hydrocarbon solvent, such as methylcyclohexane or toluene, in the desired amount of starting material and a small amount of a Friedel-Crafts type catalyst, such as
They can be prepared by reacting BF ₃ AlCl ₃ , TiCl ₄ or their complexes with e.g. ethers or phenols and keeping the reaction temperature between 0° and 80°, preferably between 20° and 50°C. .

In view of the exothermic nature of the reaction, it is recommended that the catalyst, preferably BF ₃ or a complex thereof, be added gradually. Special measures may be necessary to control the temperature during the reaction to ensure satisfactory and reproducible surgical results. The reaction mixture is kept at the desired reaction temperature (0° to 80°C) for several hours, after which the catalyst is deactivated, preferably by precipitation with aqueous hydroxide, and then the volatiles, such as the solvent and any Any unreacted starting material is removed.

The resins according to the invention can be advantageously used in adhesives, more particularly in hotmelt adhesives, which do not require the presence of organic solvents. The compatibility between resin and rubber is excellent (50:50 mixture).

In some cases, rubber-like elastomers and certain ethylene-vinyl acetate copolymers (EVA), ethyl acrylate copolymers (EEA)
and amorphous polypropylene (APP) can be used in combination or separately with these resins in hot melt pressure sensitive adhesive formulations.

The invention also provides pressure sensitive adhesives which are mixtures of resins based on alpha-methylstyrene, styrene and phenols in the amounts specified above, and elastomers such as natural or synthetic rubbers. As natural rubber, raw rubber can be used, and as synthetic rubber, any thermoelastic material (thermoelastomer) can be used, such as styrene-butadiene-styrene (SBS) and, for example, styrene-isoprene-styrene (SIS) block copolymers.

Resins and elastomers: 0.3 per part of rubber
to 3 parts, preferably between 0.5 and 2 parts by weight. Other optional ingredients such as waxes, tackifying oils (usually naphthenic petroleum) and stabilizers against oxidation and UV radiation can be included in small amounts. The resin and rubber are melted at a temperature ranging from about 80° to 200°C and held at this temperature for 10 to 30 minutes. Better results are often obtained by combining one or more rubbers or one or more resins. The use of solvents (aliphatic or aromatic hydrocarbons, their chlorinated derivatives or ketones, for example) is often not necessary, but customary additives such as antioxidants, fillers and the like can be incorporated in small amounts. Good too.

In yet another embodiment, the invention provides styrene containing 38% and at most 55% vinyl acetate.
A hot melt pressure sensitive adhesive is provided which is a mixture of a vinyl acetate copolymer and the same hydrocarbon resin as described above, and optionally a tackifying oil. The amount of resin and polymer by weight is between 35:65 and 60:40, preferably 40:60 and 50:
It can range between 50. The styrene-vinyl acetate copolymers to be applied contain from 38 to 50, preferably from 40 to 45% by weight of vinyl acetate.

In another embodiment of this invention, an ethylene-vinyl acetate copolymer comprising at least 25% and at most 55% by weight vinyl acetate;
Resins obtained by catalytic reaction of methylstyrene, styrene and phenols in mutual weight ratio mixtures as specified above, optionally with microcrystals and/or paraffin waxes and/or tackifying oils. Provided is a hot melt adhesive substantially comprising: The weight ratio of resin and copolymer can range between 35:65 and 60:40, preferably between 40:60 and 50:50. The ethylene-vinyl acetate copolymers to be applied contain from 25 to 55% by weight, preferably from 28 to 50% by weight of vinyl acetate.

Mixing of the resin and copolymer is carried out in the molten state at a temperature of 150-200°C, preferably 160-180°C, for 15-60 minutes. Small amounts of antioxidants may also be present. As the examples show, by this method:
Hotmelt adhesives can be provided which are particularly suitable for packaging, bookbinding or the production of disposable articles such as diapers, sanitary cotton, disposable salves.

When formulated as a pressure sensitive adhesive, compatibility with rubber, peel strength (measured according to PSTC-1), adhesion (measured according to PSTC-6) 25-50 microns (μm)
) and shear adhesion (PSTC-7
The balance of essential properties of certain adhesives, such as those based on α-methylstyrene, styrene, isobutene and, in some cases, phenols, is improved compared to those based solely on α-methylstyrene, styrene, isobutene and, in some cases, phenols.

The adhesive according to the invention is useful for disposable articles such as diapers and sanitary cotton, various types of tapes such as packaging tapes, screening tapes for car windows, carpeting tapes, labels, floor tiles, wall coverings,
It is particularly useful for manufacturing automobile interior parts, etc.

The pressureless hot melts formulated herein are characterized by excellent adhesion, heat and cold resistance, and stability and are useful for packaging, bookbinding, and nonpressure-sensitive disposable applications.

The invention is further illustrated by the following examples.

Example 1 64% by weight of styrene, 34% by weight of α-methylstyrene and 2% by weight of phenol are dissolved in 60 parts by weight of methylcyclohexane, calculated on the monomeric starting material, and subsequently 0.2 parts by weight of
_BF3 gas was introduced. The reaction temperature is 30° to 35°C.
After standing for a period of time, the catalyst was neutralized with sodium hydroxide and filtered, while the solvent and some unreacted starting material were stripped off. A resin with a softening point of 97°C is obtained, which is a polystyrene-polybutadiene-
Soluble in polystyrene and polystyrene-polyisoprene-polystyrene block copolymers (50:50 resin to elastomer ratio) at 30°C
This resulted in a solution with a lower cloud point. The resins have been extremely useful for hot melt adhesive compositions, particularly for hot melt pressure sensitive compositions.

Example 2 70% by weight styrene, 28% by weight α-methylstyrene and 2% by weight phenol were dissolved in 60 parts by weight of toluene and 0.2 parts by weight of BF gas were introduced (these parts by weight are monomers). (calculated for physical substances). Reaction and finishing conditions are as in Example 1.
As written inside. A resin with a softening point of 85°C was obtained.

Example 3 63.5% by weight of styrene, 31.3% by weight of α-methylstyrene and 5.2% by weight of octylphenol were dissolved in 60 parts by weight of methylcyclohexane, after which 0.3 parts by weight of BF ₃ gas were introduced. Reaction and work-up conditions were as described in Example 1. A resin with a softening point of 85° C. is obtained, which is completely soluble in polystyrene-polyisoprene-polystyrene and polystyrene-polybutadiene-polystyrene block copolymers (50:
50), yielding a clear solution with a cloud point below 30°C.

Example 4 61% by weight styrene, 32% by weight α-methylstyrene and 7% by weight phenol are dissolved in 80 parts of styrenecyclohexane and 0.25 parts by weight of
Introduced BF ₃ . Reaction and work-up conditions were as described in Example 1. A resin with a softening point of 80° C. was obtained, which was completely compatible (50:50) with ethylene-vinyl acetate and polystyrene-polybutadiene/polyisoprene-polystyrene block copolymers containing 40% vinyl acetate. .

Example 5 60% by weight of styrene, 31.5% by weight of α-methylstyrene and 8.5% by weight of phenol were dissolved in 70 parts of toluene and 0.2 part of BF ₃ gas was introduced. Reaction and work-up conditions were as described in Example 1. The resin thus obtained was heated to 70°C.
It had a softening point of , and had properties comparable in terms of compatibility to those of the resins in the previous examples.

Example 6 60% by weight of styrene, 31% by weight of α-methylstyrene and 9% by weight of phenol are dissolved in 70 parts by weight of toluene, calculated on the total weight of monomeric material, and 0.2 part of BF ₃ is introduced. did. The reaction temperature was 50 DEG -55 DEG C., and after maintaining this temperature for 4 hours, the catalyst was neutralized with aqueous NaOH and filtered, and the volatiles were stripped off. The resin thus obtained exhibits a softening point of 65 ± 5°C and
% of vinyl acetate and polystyrene-polybutadiene-polyisoprene block copolymers at a weight ratio of 50:50.

Example 7 50 parts by weight of the resin obtained in Example 5 was mixed with 100 parts by weight of a thermoelastomer (polystyrene-polyisoprene-polystyrene block copolymer,
Specific gravity 0.93, shear adhesive strength 250) and mixed with 16 parts naphthenic petroleum. After adding 5 parts of dibutylzinc dithiocarbamate, mixing was carried out at 100°C for 15 minutes. The mixture thus obtained is a useful hot-melt pressure-sensitive adhesive, particularly suitable for permanent labels on bottles, and exhibits the following properties: Peel strength 450 g/cm Shear adhesion Adhesive for more than 24 hours Force 17cm.

Example 8 30 parts by weight of the resin of Example 5, 70 parts by weight of thermoelastomer as described in Example 6, and 3 parts of dibutylzinc dithiocarbamate were mixed at 130° C. for 15 minutes to form a carpet installation tape. A particularly useful homogeneous hot melt pressure sensitive adhesive has been produced. The properties of the adhesive were as follows: Peel strength: 805 g/cm Shear adhesion: Adhesion over 25 hours: 9 cm.

Example 9 12 parts by weight of the resin of Example 5, 100 parts of Example 6
The thermoelastomer described in Example 1, 40 parts of naphthenic petroleum and 5 parts of dibutylzinc dithiocarbamate were mixed for 15 minutes at 100°C to yield a pressure sensitive adhesive particularly useful as a packaging tape. Its properties were as follows: Peel strength: 300 g/cm Shear adhesive strength: Adhesive strength over 24 hours 15 cm.

Examples 10 and 11 50 parts by weight of the resin of Example 5 and 50 parts by weight of an ethylene-vinyl acetate copolymer containing 40% by weight of vinyl acetate (melt index measured according to ASTM D 1238: 40-70 g/10 min). Melt mixing was carried out at a temperature of approximately 165°C. A hotmelt pressure-sensitive adhesive was thus obtained which is highly suitable for use in the production of diapers, sanitary cotton and the like.

An excellent adhesive was obtained in a similar manner by mixing resin and polymer in a ratio of 40:60.

The following properties were measured for the 50:50 and 40:60 mixtures, respectively: Peel strength 670 580 g/cm Shear adhesion 24 and above 24 and above Time adhesion 3.5 6.5 cm Examples 12 and 13 In Example 10 Two hot melt pressure sensitive adhesives were prepared by mixing an amount of the resin of Example 6 with an ethylene-vinyl acetate copolymer containing 45% vinyl acetate (melt index 25 g/10 min, measured according to ASTM 1238) according to the method described. A drug was prepared.
The weight ratios of the resin and copolymer mixtures were 50:50 and 40:60. The melting/mixing temperature was 180°C. These hot melt pressure sensitive adhesives have also proven particularly suitable for bonding diapers, sanitary cotton and other disposable items.

The following properties were measured for each of the 50:50 and 40:60 mixtures: Peel strength 640 500 g/cm Shear strength 24 and above 24 and above Time adhesion 3.6 6.6 cm.

Example 14 A standard hot melt was prepared according to the following recipe: 30 parts ethylene-vinyl acetate resin (containing 28% vinyl acetate); 50 parts resin; 20 parts microcrystalline wax (melting point 82
°C); 0.5 part di-tert-butyl-paracresol.

Two such compositions were evaluated and compared; the first resin was the resin described in Example 5, and the second was a commercially available copolymer, α-methylstyrene, having the following properties: It was styrene (without phenol): Softening point: 85℃ (R+B) Color: Colorless Acid value and saponification value: <1 Specific gravity (25℃): 1.06 Both compositions are suitable for hot melt for joining polyethylene to non-woven fabrics. It was evaluated as an adhesive.

Commercially available resin-based adhesives gave poor (zipper-like) bonds between polyethylene and nonwovens, whereas other adhesives of this invention gave strong (destructive or tear-off) bonds. gave.

Claims (1)

Claims: 1. A resin useful in adhesives based on α-methylstyrene, styrene and phenol as components, wherein substantially the total weight percentage of α-methylstyrene, styrene and phenol is 25% each. to 63, 35 to 73, and 2 to 15, and this resin has a softening point of 70°C to
A resin characterized by having a temperature of 120°C and an average molecular weight of 400 to 2000. Resin according to claim 1, characterized in that the weight percentages of the two components range from 25 to 57, from 40 to 72 and from 3 to 10, respectively. 3 Structural formula of phenol: The resin according to claim 1 or 2, wherein R is hydrogen or a C ₁ -C ₁₂ alkyl group. 4 α-methylstyrene, which is substantially the total component;
α-methylstyrene containing styrene and phenol in the range of 25 to 63% by weight, 35 to 73% by weight and 2 to 15% by weight, respectively, and has a softening point of 70°C to 120°C and an average molecular weight of 400 to 2000. , a method for producing resins useful in styrene and phenol based adhesives, in which the components are heated to 0°C.
BF ₃ as a catalyst at temperatures from to 80°C,
α-methylstyrene, characterized in that it is reacted in the presence of AlCl ₃ , TiCl ₄ or their complexes with ethers or phenols to deactivate and remove the catalyst and to remove any volatiles;
Process for producing styrene and phenol based resins.