JPH0286676A - Hot-melt adhesive composition - Google Patents

Abstract

PURPOSE:To obtain the title composition prevented from undergoing peeling or loss of strength at low temperatures and improved in a cohesive force, etc., by mixing a specified amorphous propylene/butene-1 random copolymer with a tackifier and a resin. CONSTITUTION:30-100wt.% amorphous propylene/butene-1 random copolymer having a number-average MW of 1000-20000, a butene-1 content of 10-60wt.%, a tensile elongation at break >=200%, a ring and ball softening point <=120 deg.C, an n-heptane-insoluble content <=20wt.% and an open time <=60sec is mixed with 0-70wt.% tackifier (e.g., cycloaliphatic petroleum resin), 0-70wt.% resin (e.g., styrene/ethylene/butylene/ styrene block copolymer) and, optionally, an oil, a filler, an antioxidant, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a hot melt adhesive composition containing a non-grade propylene-butene-1 random copolymer.

[Prior Art] Conventionally, hot melt adhesives containing polypropylene as a main component have been used as adhesives for polyethylene and polypropylene films. In particular, low-viscosity hot-melt adhesives are mainly composed of non-quality acidic polypropylene.

[Problems to be Solved by the Invention] Non-quality active polypropylene has been obtained as a by-product in the production of raw isotactic polypropylene and has been used with the advantage of being inexpensive.

However, the active polypropylene that is produced as a by-product from homopolypropylene and random copolymers has propylene as its main component and does not have good low-temperature properties, and the components of those that are produced as a by-product from block copolymers are not uniform (quality is poor). It wasn't constant.

In addition, since it is a by-product, its viscosity, softening point, hardness, etc. vary depending on the physical properties of the product, the polypropylene, and it has been particularly difficult to appropriately prepare a product with a desired melt viscosity.

Furthermore, as polypropylene catalysts become more highly active,
It is said that the amount of by-products from the production of isotactic polypropylene is decreasing, and the production of hot-melt adhesives from the production of isotactic polypropylene using by-products from the production of isotactic polypropylene will have to end at an early stage. .

The present inventors previously proposed a hot melt adhesive containing a non-grade propylene/ethylene random copolymer as a main component (Japanese Patent Application No. 63-94475). This method actively produces a non-grade propylene/ethylene random copolymer and uses it in adhesives without using non-grade active polypropylene, which is a by-product of isotactic polypropylene production. .

The previously proposed adhesive made of a non-grade propylene/ethylene random copolymer has excellent low-temperature properties, but has a low tensile elongation at break of 200% or less, and a ring and ball softening point of 120°C or higher. Since the oven time is 60 seconds or less, the coating must be performed at a high temperature of 120° C. or higher, and the time from coating to bonding to the adherend is also limited.

In addition, it is not suitable as a hot melt adhesive especially for disposable diapers because of its low cohesive strength.

Therefore, the present inventors investigated the drawbacks of hot melt adhesives mainly composed of the above-mentioned non-quality propylene/ethylene random copolymer, and found that they maintain heat resistance and do not peel off or lose strength at low temperatures. The present invention was achieved as a result of intensive research aimed at obtaining a hot melt adhesive that has a large cohesive force, a relatively low application temperature, and a relatively long oven time.

(Means for solving a!l!a) According to the present invention, (a) the number average molecular weight is 1,0002
0,000 and 10-60% by weight of butene-1-containing stars;
Consisting of double star% and (C) resin 'MO-70 heavy star%,
And, the non-quality propylene-butene-1 random copolymer has a tensile elongation at break of 200% or more, a ring and ball softening point of 120°C or less, an n-heptane insoluble content of 20% or less, and an oven time of 60 seconds. A hot melt adhesive composition is provided.

The non-quality propylene-butene-1 random copolymer of the present invention (hereinafter simply referred to as random copolymer) can be produced by using, for example, a titanium-supported catalyst in which titanium is supported on magnesium chloride and triethylaluminum. It is produced by copolymerizing a mixture of liquefied propylene and liquefied butene-1. The random copolymer produced in this way is of poor quality, contains 10-60% by weight of liquefied butene-1, and has a number average molecular weight ffi of 1,00120,000, and is suitable for the production of Aitutakuchi and Ivy polypropylene. Compared to the by-produced acidic polypropylene, properties such as softening point and melt viscosity can be obtained with stable quality within a certain range, and the quality is uniform when used as an adhesive. Further, by appropriately selecting the copolymerization ratio and molecular weight of propylene/butene-1, the softening point and melt viscosity can be set within a desired range. Furthermore, since no solvent is used, there is no risk of ignition or odor problems.

The random copolymer of the present invention has a number average molecular weight of 1.00
0-20,000, the butene-1 content is adjusted to 10-60%, but if the number average molecular weight is less than 1,000, the cohesive force is small and sufficient adhesive strength cannot be obtained; If it exceeds 000, the melt viscosity will be high, causing problems in workability, the difference in viscosity from other compounding agents will be large, making blending difficult, and fluidity will be insufficient, resulting in uneven coating, which is not preferable. In addition, the butene-1 content is 10%
If it is less than 120° C., the shearing point will be high, and if it is more than 60%, the softening point will be extremely low, making it unsuitable as a raw material for hot melt adhesives.

Even if the random copolymer of propylene and butene-1 is within the above number average molecular weight and butene-1 content, various properties differ depending on the randomness of the copolymerization of propylene and butene-1. The random copolymer used in the present invention has an elongation at break of 200% or more, a ring and ball softening point of 120'C or less, and an n-hebutane insoluble content of 20% or more.
% or less, and the oven time is 60 seconds or more.

If the elongation at tensile break is less than 200%, the cohesive force will be low and the strength at the time of cohesive peeling will be low, which is not preferable.

In particular, it is not suitable for uses such as disposable diapers that require cohesive strength during peeling. If the softening point exceeds 120'C, the coating temperature will also exceed 120'C, and the adherend will have a melting point of 1.
If the temperature is below 20'C, for example, low density polyethylene (L
DPE) film, linear low density polyethylene (LLD)
PE) It is not preferable to melt the film etc. If the "n-hebutane insoluble" content exceeds 20%, it means that the random copolymer has a fairly high crystallinity, which not only causes undesirable solidification after application, which shortens the oven time, but also causes problems in adhesion. The cohesive force and
This is undesirable because it may change the shape of the peeled moon or lead to volumetric shrinkage after application. In addition, if the oven time is less than 60 seconds, the time required for the adhesive to harden is short, and the adherend must be crimped in a short time after the adhesive is applied.
Unfavorable for work. In particular, it is undesirable because it restricts its use in continuous production lines where several types of parts are bonded together, continuous production lines where production speeds are varied, and the like.

Although the random copolymer of the present invention has the above-mentioned properties, it may be produced as described above, or a commercially available copolymer may be used to obtain the properties of the random copolymer of the present invention. It is also possible to select and use the ones that have the following properties as appropriate.

In the present invention, the random copolymer can be used alone, but if the adherend has difficulty adhering to the copolymer, tackifiers and resins may be added to improve the adhesive properties. It can be used by increasing the adhesive strength, changing the compatibility with the adherend, changing the viscosity during melting (coating), and adjusting the setting force. Further, as the random copolymer, one modified with an acid such as maleic anhydride can also be used.

When blending a tackifier or the like, the blending ratio of the random copolymer is preferably 30% or more. If it is less than 30%, the properties of the random copolymer are hot nor l-
This is not reflected in the adhesive and is not desirable.

Tackifiers used in the present invention include natural rosin (gum rosin, wood rosin, tall oil rosin, etc.),
Modified rosin (polymerized rosin, hydrogenated rosin, maleated rosin, etc.), coumaron/inten resin, terpene resin,
Petroleum resin, phenolic resin, etc. can be used. In addition, the resins include ethylene/vinyl acetate copolymer,
Ethylene/acrylic acid copolymer, ethylene/ethyl acrylate copolymer, ethylene/methyl acrylate copolymer, styrene/ethylene/butylene/styrene block copolymer, ethylene/propylene copolymer with molecules of 130,000 or more Alternatively, ethylene-butene copolymers, polybutenes, waxes, and polymers and copolymers modified with these acids, metal salts of acids, halogens, etc. can be used. These tackifiers and resins can be used alone or in combination of two or more.

The adhesive obtained by blending the above-mentioned tackifier and/or resin with the random copolymer of the present invention has various properties such as tensile elongation at break, ring and ball softening point, and oven time that the random copolymer has. These characteristics remain unchanged regardless of the composition of the compound, and in particular, the softening point is relatively low, and the solidification after application is maintained at approximately the same oven time as the random copolymer. It will be eroded due to the adhesive work. Moreover, the adhesive effect becomes even higher.

In addition, paraffinic, naphthenic, aromatic, and other oils may be added as compounds other than those listed above, and in order to adjust melt viscosity and fluidity. Furthermore, conventionally known additives, such as various fillers and antioxidants, may be added. As fillers, clay, talc, calcium carbonate, barium carbonate, etc., and organic and inorganic fibrous reinforcing materials can also be used. Antioxidants include dilauryl thiodipropionate, 2,6-ditardiaso-butyl-
4-Methylphenol, tetrakis[methylene-3(3
, 5-di-butyl-4-hydroxyphenol)propionate]methane, distearylthiodipropionate, distearylpentaerythritol diphosphite, and the like can be used.

Even when these compounds are added, the resulting adhesive has no fear of deteriorating the properties of the random copolymer, has an excellent adhesive effect, and maintains high workability.

In the present invention, in order to blend other polymers and fillers of the random copolymer, it is sufficient to simply mix, heat and stir these components in a container, or it is sufficient to mix the other polymers and fillers in the random copolymer. -OJ)? n
It is also possible to use rolls, high-pressure mixers, niegoos, extruders, etc., which are used for mixing.

Since the adhesive of the present invention melts when heated, it can be molded into various shapes such as a block, a pellet, a string, and a film.

The adhesive of the present invention can be melted onto adherends using a normal hot melt adhesive applicator and bonded to each other, or the adhesive can be applied to one of the adherends in advance, and then the adhesive can be applied to the other. Either a method of stacking two adherends together and heating them, or a method of pasting together a film-like adhesive using a laminator may be adopted.

Adherents to which the adhesive of the present invention can be used include paper, cloth,
Examples include wood, synthetic resins such as polyethylene, polypropylene, and polyvinyl chloride, as well as plaster, cement, stone, and metal.

As a particularly preferred example, a disposable disposable diaper has a waterproof polyethylene fill 1 as the outermost layer and a polypropylene fill as the inner layer.
! Alternatively, it can be used for adhesion to non-woven fabrics made of polyethylene terephthalate.

In addition, moisture-proof/waterproof paper with a sandwich-like structure made by laminating paper and/or paperboard with hot-melt adhesive, and moisture-proof/waterproof paper with hot-melt adhesive applied to one side of paper and/or paperboard. is also applicable.

Furthermore, it is also used to fill gaps between objects made of the same or different materials as described above as adherends, and as a sealant.

The characteristics used in the present invention were measured by the following method.

1, N''1. Average molecular weight: Measured using gel permeation chromatography (CPC) at a temperature of 135° C. using orthodichlorohenzene (ODCB) as a solvent.

2. Butene-1 content: Measured using nuclear magnetic resonance spectroscopy (JEOL FX-200 model).

3. Elongation at tensile break tJJr: Measured at a tensile strength of 50 mm/min and a temperature of 24° C. using a No. 2 type test piece based on JIS K 7113.

4. Ring and ball softening point: Measured based on JIS K 2207.

5. Pour n-heptane into a Soxhlet extractor for n-heptane insoluble matter and leave it in a boiling state for 6 hours. The sample is dried in a vacuum dryer at 60° C. and then weighed.

n-Hebutane insoluble matter (weight after extraction/weight before extraction)
xlOO (%) 6. Oven time: Drop the polymer or adhesive heated to 190'C onto kraft paper fixed on a glass plate, and apply to a thickness of 60 μm using a bar coater preheated to 190'C.

The same type of kraft paper is laminated thereon at predetermined time intervals such as 0.10, 20.30 seconds, etc., and immediately pressed with a rubber roller. 5 minutes after pasting, add 1. IJH
The oven time was defined as the final time when the paper and polymer or adhesive could not separate at the interface and cohesive peeling or paper tearing occurred.

〔Example〕

El Paso Products Company (Ee Paso Products Company) shown in Table 1
70 wt.
Product name: Alcon P-125) 30% by weight and 160'
The adhesives were mixed by heating and melting at C to prepare adhesives 1 and 2.

Furthermore, a thermoplastic elastomer (manufactured by Neru Chemical Co., Ltd.: Kraton G1657 ) 15% by weight, fatty acid petroleum resin from Arayo Kagaku Co., Ltd. (trade name: Alcon P-) as a tackifier
125) and 30% by weight were heat-melted and mixed at 180'C to obtain Adhesive 3.

Adhesives 1.2 and 3 were then applied at 105° C. onto a polypropylene fiber nonwoven fabric and immediately treated with LLD.
A film having a thickness of Pε of 20 μm was pressure-bonded to obtain a bonded test piece A. Further, at a coating temperature of 150° C., after standing for 30 seconds, LLDPE film 1 was similarly bonded and bonded to obtain test piece B.

Cut each test piece into 25 mm wide strips and peel at Alt speed 3.
The appeal speed was measured at 00 mm/min, the adhesive strength was tested, and the damage state of the LLDPE film was also investigated.

The results are shown in Table 3.

(Comparative example) A non-grade propylene ethylene copolymer manufactured by El Paso Products Company, USA shown in Table 2 was used instead of a non-grade propylene butene-1 random copolymer, and heated and melted at 180"C. Adhesives 4 and 5 were prepared in the same manner as in the example except for the following.

Further, Adhesive 6 was prepared in the same manner as in Example by using instead of the propylene-butene-1 random copolymer manufactured by Huls AG, West Germany shown in Table 2, and heating and melting at 160°C.

Apply these adhesives 4.5 and 6 at a temperature of 140°C.
Test piece C was prepared at 125°C or 105°C in the same manner as in the examples, and after being left at a coating temperature of 150"C for 30 seconds, an LLDPE film was bonded together to obtain a test piece, and an adhesive strength test was conducted in the same manner. The results are shown in Table 3.

Table 2 [Effects of the Invention] The hot melt adhesive composition of the present invention uses a specific non-grade propylene-butene-1 random copolymer that can be obtained with stable quality. A product with high adhesive strength at high temperatures can be obtained. Furthermore, since the bonding temperature can be maintained at a relatively low temperature, it is also possible to bond polyethylene films.

Therefore, the hot melt adhesive of the present invention not only easily bonds paper, wood, plastic, stone, plaster, cement, metal, etc., but is also particularly suitable for bonding polyethylene film and nonwoven fabric of disposable Gi diapers. It is industrially useful. Furthermore, solidification after application is slow and workability is excellent.

Claims (1)

[Claims] (1) 30-100% by weight of amorphous propylene-butene-1 random copolymer with a number average molecular weight of 1,000-20,000 and a butene-1 content of 10-60% by weight, adhesive Imparting agent 0-70% by weight, and resins 0-7
0% by weight, and the elongation at tensile break of the non-grade propylene-butene-1 random copolymer is 200%.
As described above, the hot melt adhesive composition has a ring and ball softening point of 120° C. or less, an n-heptane insoluble content of 20% or less, and an oven time of 60 seconds or more.