JPH0345100B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing an adhesive composition. More specifically, the present invention relates to a method for producing an adhesive composition that can be effectively used as a hot melt adhesive for various substrates. [Prior Art] In general, base materials made of polyolefin, polyester, polyamide, aluminum, steel, leather, etc., especially smooth base materials, are bonded to each other or bonded to porous materials such as paper, wood, synthetic resin foam, etc. Laminated with packaging materials, industrial materials, automobile parts,
It is used in many fields such as building parts, household goods, medical supplies, and sporting goods. Adhesives are used when laminating these various products, but the physical properties required of these adhesives are diverse and differ depending on the field of application, but among these physical properties, there are some common requirements. There are two things that can be mentioned: adhesive strength and heat resistance. Of the many adhesives currently in use, only solvent-based adhesives simultaneously and fully satisfy these requirements. It has been applied to substrates whose surfaces have been treated with plasma or the like. However, when such solvent-based adhesives are used, they not only require drying and solvent recovery steps, but also always pose problems such as environmental deterioration due to solvent vapor and the risk of fire. Therefore, it is desired to develop a hot melt adhesive that does not have such problems and has excellent adhesive strength and heat resistance. As hot-melt adhesives, adhesives consisting of components such as ethylene-vinyl acetate copolymer, tackifier, and wax have been widely used. are unsatisfactory in terms of adhesive strength and heat resistance, especially when applied to smooth substrates. As an adhesive composition that can also be applied to smooth substrates,
A composition consisting of a low-crystalline ethylene-α-olefin copolymer and an ethylene-vinyl acetate copolymer, in which at least one of them is graft-modified with an unsaturated carboxylic acid or its acid anhydride, has been proposed ( (Japanese Patent Application Laid-open No. 13718/1983). Although it is true that this adhesive composition has improved adhesion to smooth substrates compared to the hot melt adhesive based on the ethylene-vinyl acetate copolymer described above, the improvement effect is still not sufficient. No improvement effect on heat resistance was observed. In addition, a hot-melt adhesive has been proposed in which a mixture of ethylene-propylene copolymer rubber and crystalline or non-crystalline polypropylene is subjected to a melt-mixing reaction in the presence of an organic peroxide to reduce its viscosity. (Japanese Unexamined Patent Publication No. 55-48236), although this adhesive may show improved heat resistance, it has been confirmed that it has poor adhesion to smooth substrates. [Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing an adhesive composition that can be sufficiently applied to smooth substrates as a hot melt adhesive and can impart sufficient adhesive strength thereto. There is a particular thing. [Means for Solving the Problems] An adhesive composition that achieves the object of the present invention comprises (a) 90 to 50% by weight of a peroxide-decomposed non-crystalline to low-crystalline olefin copolymer; (b) Consists of 10 to 50% by weight of a peroxide-decomposable crystalline olefin polymer, in which at least one of these (a) and (b) amphoteric components is (c) an unsaturated carboxylic acid or its acid anhydride. (d) an organic peroxide; and (d) an organic peroxide. Examples of the peroxide decomposition type amorphous to low crystalline olefin copolymer used as component (a) include propylene-ethylene copolymer, butene-1-ethylene copolymer, propylene-butene-1 In the case of a copolymer, the proportion of the comonomer that influences the degree of crystallinity is 50 mol% or more, preferably 55 mol% or more in the case of an ethylene-based copolymer, and preferably 55 mol% or more. are used. Among these olefin copolymers, the most preferable one from the viewpoint of flexibility is propylene-based copolymers.
It is an ethylene copolymer, and in view of rubber properties and viscosity reduction, it is particularly preferable that the propylene content is 55 to 80 mol%. That is, if the propylene content exceeds this range, the crystallinity will increase and flexibility will be lost, while if the propylene content is below this range, the viscosity will become too high. When these copolymers are kneaded with an organic peroxide under heating, the decomposition reaction takes precedence over the crosslinking reaction, resulting in a marked increase in fluidity. Examples of the peroxide-decomposed crystalline olefin polymer of component (b) include isotactic polypropylene, copolymers of propylene and other olefins, and polybutene-1. These crystalline olefin polymers have a melting point of about 100~
A temperature of 200°C, preferably about 110 to 170°C, and a crystallinity of about 25% or more is preferably used. Those with a melting point higher than this or those with a crystallinity lower than this are not suitable for improving heat resistance, which is the objective of the present invention, while those with a melting point higher than this are used within the temperature range used as a hot melt adhesive. This makes it unsuitable for the purpose of improving liquidity in
When these crystalline olefin resins are kneaded with an organic peroxide under heating, they are thermally decomposed to increase fluidity and also play a role in improving heat resistance. In the polymer component consisting of the above components (a) and (b), component (a) is 90 to 50% by weight, preferably 80 to 60% by weight, and component (b) is 10 to 50% by weight, preferably 20
It is used in a proportion of ~40% by weight. If the proportion of component (b) exceeds this range, the flexibility and adhesiveness of the composition will be impaired, while if it is used in a proportion below this range, the heat resistance and fluidity of the composition will be impaired. Examples of the unsaturated carboxylic acid or its acid anhydride as component (c) include maleic acid, fumaric acid, itaconic acid, acrylic acid, methacrylic acid, crotonic acid,
maleic anhydride, itaconic anhydride, sorbic acid,
Cinnamic acid, vinyl acetic acid, etc. are used, and among these, maleic anhydride, which is difficult to radically polymerize alone, is preferably used. These unsaturated carboxylic acids or their acid anhydrides can be treated as described above in the presence of an organic peroxide.
By heating and kneading with at least one of component (a) and component (b), it is graft copolymerized with these polymer components. In this case, (a) component or
It is not necessary to use the entire amount of component (b) in the graft copolymerization, and the remainder not used in grafting can be used as an unmodified component when mixing with component (d).
The unsaturated carboxylic acid or its acid anhydride is used in an amount of 0.01 to 5 parts by weight, preferably 0.01 to 5 parts by weight per 100 parts by weight of the resin component, as a grafting amount of the graft modified component of the polymer.
It is used in an amount of 0.5 to 3 parts by weight, more preferably 1 to 2 parts by weight. If it is used in an amount greater than this, the coloring will be intense, while if it is less than this, the adhesive force will be insufficient. Examples of the organic peroxide component (d) used for the decomposition reaction and grafting reaction of the polymer component include dicumyl peroxide, ditert-butyl peroxide, 2,5-dimethyl-2,5-di( tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)hexane,
butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tertiary
butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide,
2,4-dichlorobenzoyl peroxide, tertiary
Examples include butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and tert-butyl cumyl peroxide. These organic peroxides are used in an amount of 0.01 to 3 parts by weight, preferably 0.05 to 1 part by weight, and more preferably 0.1 to 1 part by weight per 100 parts by weight of the resin component. In addition, the adhesive composition of the present invention may contain ethylene-vinyl ester copolymer, ethylene - An unsaturated carboxylic acid (ester) copolymer or the like can also be used in combination. The adhesive composition is prepared by combining the above-mentioned components using a Banbury mixer, a kneader, a melting tank with a stirrer, an extruder, etc., and adding the amphoteric components (a) and (b) in which at least one of them has been graft-modified. After melting and kneading at a temperature above the decomposition temperature of component (d), it is once formed into granules, flakes, pellets, rods, etc., and used in various adhesive methods. When melting and kneading each component (a), (b), and (d) in an extruder, the melting of the product may be insufficient due to insufficient residence time in the extruder or poor kneading performance of the extruder. If the index is insufficiently increased or the heat resistance improvement effect is insufficient, the desired adhesion can be achieved by further adding organic peroxide or by melting and kneading with an extruder again without any additives. Compositions can also be obtained. In addition, considering the capacity and performance of the extruder, after kneading the non-graft-modified component (a), component (b), and component (d) in the first extruder, (a) component or (b) component graft-modified in an extruder and
It is also possible to adopt a method of adding component (d). What is important when preparing the adhesive composition of the present invention is to coexist components (a) and (b), at least one of which has been graft-modified, and to mix them in the presence of the organic peroxide component (d). The object of the present invention can only be achieved by melting and kneading the polymer components, simultaneously carrying out the cleavage and decomposition reaction of the polymer components and the melt work. For example, if the graft-modified components (a) and (d) are melted, kneaded, decomposed and modified, and then this decomposition product and component (b) are simply melted and kneaded, it will not work as in the present invention. It is not possible to obtain an adhesive composition with excellent heat resistance. In addition, compared to a composition consisting only of both components (a) and (b) in which at least one of them has been graft-modified, the composition of the present invention has a high adhesive strength, especially when a hot melt adhesive is prepared from it. Not only that, but it is also significantly superior, especially in terms of shear adhesive failure temperature. The adhesive composition of the present invention containing the above-mentioned components as basic essential components may include a tackifier resin,
A hot melt adhesive can be prepared by blending wax, plasticizer, filler, antioxidant, etc. Examples of the tackifying resin include rosin or its derivatives, terpene resins, terpene-phenol resins, aromatic, aliphatic, alicyclic or copolymerized petroleum resins, coumaron-indene resins, styrene resins, etc. From the viewpoint of compatibility and adhesiveness, terpene resins and alicyclic petroleum resins are particularly preferred, and from the viewpoint of heat resistance, terpene resins are particularly preferred.
It is used in a proportion of 20 to 200 parts by weight, preferably about 50 to 150 parts by weight. Examples of the wax used as a viscosity reducing agent for the composition include paraffin wax, microcrystalline wax, polyethylene wax,
Examples include polypropylene waxes, which are generally used in an amount of about 50 parts by weight or less per 100 parts by weight of the adhesive composition. When this composition is used as an adhesive that can be applied with a hot melt applicator, its viscosity (at 180°C) is approximately 100 Pa.
S or less, preferably about 50 Pa.S or less, so by adjusting the blending amount of each component,
The viscosity of the composition is adjusted to the desired degree. The adhesive composition prepared in this manner is preferably in the form of a hot melt adhesive, such as polyethylene, polypropylene, polystyrene, hard or soft vinyl chloride resin, ethylene-vinyl acetate copolymer, or a saponified material thereof. , films, sheets, foams, nonwoven fabrics, and other molded products made of various resins such as polyester, polyamide, ethylene-acrylic acid (ester) copolymer, and ionomer resin, and smooth materials such as aluminum foil, copper foil, steel plates, paper, and wood. It can be used as an effective adhesive for various base materials including base materials. Application of adhesive compositions to these substrates is
For example, this can be done by the following method. (1) Heat fusion method A method in which a film or sheet of an adhesive composition formed by an inflation method, T-die method, etc. is sandwiched between base materials and heat fused, or at least one of the base materials A method in which an adhesive composition is laminated in advance on one side using a coextrusion method, an extrusion coating method, etc., and then the other base material is laminated. Method of laminating base materials via a molten film (3) Co-extrusion method If the base material can be extruded, a method of co-extrusion laminating all the constituent layers including the adhesive composition using an extrusion molding method ( 4) Hot-melt method A method of applying an adhesive composition to which a tackifier resin, wax, etc. are added as necessary to a base material using a hot-melt gun, roll coater, extrusion coater, etc., and bonding by pressing [Invention] [Effect] The adhesive composition according to the present invention has good adhesive strength and heat resistance, so it can be used as an adhesive, especially a hot melt adhesive, even for materials having at least one smooth substrate. It can be effectively used as In particular, the adhesive composition of the present invention can provide good adhesion and heat resistance to polypropylene, which has traditionally been difficult to adhere to among smooth substrates, or to other substrates. must be said to be noteworthy. [Example] Next, the effects of the present invention will be explained with reference to Examples. The compositions prepared in each Example and Comparative Example were evaluated as follows. Adhesive strength: (a) Heat sealing method Hot melt adhesive is heated and melted at 180℃,
A 0.2 mm thick sheet was produced using a heat press.
This adhesive sheet is sandwiched between adherends, and using a heat sealer, the sealing width is 25mm, the sealing temperature is 160℃ (the temperature of the top and bottom surfaces of the seal bar), the sealing pressure is 3Kg/cm ² G, and the sealing time is 5 seconds. After heat-sealing under the following conditions, the sample was cut to a width of 25 mm, and the T-peel strength of this sample was measured using an Instron tensile tester at a tensile speed of 300 mm/min and a temperature of 23°C. (b) Hot melt applicator method Hot melt adhesive is heated and melted at 180°C.
Using Nordson hot melt applicator, open time 5 seconds, press pressure 3 kg/
After crimping under the conditions of cm ² G and a press time of 5 seconds, a 25 mm wide sample was prepared, and this sample was tested using an Instron tensile tester at a tensile speed of 300 mm/min.
T-peel strength was measured at a temperature of 23°C. The adherends for these adhesive strength measurements were polypropylene film (PP: Mitsui Petrochemical's inflation film made from polypropylene, thickness 200μ), polyethylene terephthalate film (PET: Toray product Lumirror,
200μ thick) and a soft aluminum plate (Al/200μ thick) were used, respectively. Melt viscosity: The melt viscosity of a hot melt adhesive at 180°C was measured using a B-type rotational viscometer. Shear adhesive failure temperature: In the adhesive strength measurement method, the adhesive sheet was sandwiched between kraft paper and heat sealed under the same conditions, then a 25 mm wide sample was prepared, and a 1 kg load was applied to it at 0.3°C/ The falling temperature was measured when the temperature was raised at a temperature increase rate of 1 minute. Furthermore, the melt flow rates of each component (a) and (b) used were both measured at 190°C. Example 1 Crystalline polypropylene (melt flow rate
15) 100 parts, 1.5 parts of maleic anhydride and 2,5-
30.2 parts of dimethyl 2,5-di(tert-butylperoxy)hexyne was added to a dry blend, and this mixture was heated to a resin temperature of 300 using an extruder with a diameter of 65 mm (L/D = 28, using an intermediate Dalmage screw). The graft reaction was carried out at ℃. Furthermore, instead of crystalline polypropylene, the same amount of propylene-ethylene copolymer rubber (propylene content 60 mol %, melt flow rate 0.29) was used and grafted. 30 parts of the thus obtained maleic anhydride grafted modified product of crystalline polypropylene (maleic anhydride grafted amount 1.5%) and maleic anhydride grafted modified product of propylene-ethylene copolymer rubber (maleic anhydride grafted amount 1.5% by weight)
70 parts and 30.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne were dry blended, and the mixture was heated at 300°C using an extruder with a diameter of 65 mm.
It was extruded into pellets. Comparative Example 1 In Example 1, 2,5-dimethyl-2,5
-di(tert-butylperoxy)hexyne-3 was not used. Regarding the adhesive compositions obtained in the above Examples and Comparative Examples, the melt flow rate (190°C,
2160g), shear adhesive failure temperature, and adhesive strength by heat sealing method were measured. The results obtained are shown in Table 1 below.

[Table] Example 1
Compare 32 99 1300 1620
Example 1
Example 2 40 parts of the adhesive composition of Example 1, terpene resin as tackifying resin (cheap crude oil product YS Resin)
Px1000) and 20 parts of microcrystalline wax (Nippon Seigai Seisen Rubax 2191) were placed in a kneader and kneaded at 200 to 220°C for 1 hour to prepare a hot melt adhesive. For the hot melt adhesive thus prepared, melt viscosity, shear adhesive failure temperature, and adhesive strength by heat sealing method were measured. Comparative Example 2 In Example 2, the same amount of the composition of Comparative Example 1 was used in place of the adhesive composition of Example 1. The measurement results for the hot melt adhesives obtained in Example 2 and Comparative Example 2 are shown in Table 2 below.

[Table] Example 3 100 parts of the crystalline polypropylene, 5 parts of maleic anhydride, and 30.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne were dry blended, and the mixture of Example 1 and The graft reaction was carried out in the same manner. Maleic anhydride grafted modified product of the obtained crystalline polypropylene (maleic anhydride graft amount
1.5% by weight), 70 parts of the propylene-ethylene copolymer rubber used in Example 1, and 30.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne were dry blended, This is the caliber
The mixture was extruded into pellets using a 65 mm extruder at a resin temperature of 300°C. Example 4 70 parts of the modified maleic anhydride grafted onto the propylene-ethylene copolymer rubber of Example 1, 30 parts of crystalline polypropylene, and 2,5-dimethyl-2,
5-di(tert-butylperoxy)hexyne-30.2
The mixture was dry blended and extruded into pellets using an extruder with a diameter of 65 mm at a resin temperature of 300°C. Comparative Example 3 In Example 3, the maleic anhydride graft modified product of crystalline polypropylene and the propylene-ethylene copolymer rubber were 2,5-dimethyl-2,5
-Melt blended in the absence of di(tert-butylperoxy)hexyne-3. Example 5 In Example 2, the same amount of the adhesive composition of Example 3 was used in place of the adhesive composition of Example 1. Example 6 In Example 2, the same amount of the composition of Example 4 was used in place of the adhesive composition of Example 1. Comparative Example 4 In Example 2, the same amount of the composition of Comparative Example 3 was used in place of the adhesive composition of Example 1. The (adhesive) compositions and hot melt adhesives obtained in Examples 3 to 6 and Comparative Examples 3 to 4 were evaluated in the same manner as in Examples 1 and 2. The measurement results are shown in Table 3 below.

【table】

Claims (1)

[Scope of Claims] 1 (a) 90 to 50% by weight of a peroxide-decomposed amorphous or low-crystalline olefin-based copolymer and (b) a peroxide-decomposed crystalline olefin-based polymer 10 ~50% by weight, at least one of these components (a) and (b) has been graft-modified with (c) an unsaturated carboxylic acid or its acid anhydride, and (d) A method for producing an adhesive composition, which comprises simultaneously melt-mixing an organic peroxide. 2. The method for producing an adhesive composition according to claim 1, wherein the olefin copolymer used as component (a) is a propylene-ethylene copolymer having a propylene content of 50 mol% or more. 3. The method for producing an adhesive composition according to claim 1, wherein the olefinic polymer used in component (b) is a propylene homopolymer or copolymer. 4. The method for producing an adhesive composition according to claim 1, wherein the graft modified polymer component is maleic acid or maleic anhydride graft modified product. 5. Production of the adhesive composition according to claim 1 or 4, wherein the graft modified polymer component is an unsaturated carboxylic acid or a graft modified product thereof with an acid anhydride graft amount of 0.01 to 5% by weight. Law. 6 Component (d) is 0.01 to 3 per 100 parts by weight of the polymer component
A method for producing an adhesive composition according to claim 1, wherein the adhesive composition is used in parts by weight.