KR0178047B1 - Hot Melt Adhesive Compositions for Sanitary Materials - Google Patents

Abstract

The present invention is a styrene-ethylene-butylene-styrene block copolymer (SEBS) 5-25% by weight, at least one 40-70% by weight of hydrogenated aromatic petroleum resin, hydrogenated aliphatic petroleum resin and hydrogenated terpineic resin %, Heat melting type for sanitary materials composed of total amount of paraffinic component and naphthenic component in plasticizing oil containing plasticizing oil 10 to 40% by weight, liquid rubber 5 to 15% by weight and softener 5 to 10% by weight The adhesive composition has colorless and odorless properties.

Description

Hot Melt Adhesive Compositions for Sanitary Materials

The present invention relates to a hot melt adhesive composition used for sanitary materials such as paper diapers and hygienic napkin.

Heat-melting pressure-sensitive adhesives, as is known, speed up the application of adhesive paper and adhesive tapes compared to solvent-based adhesives, and do not require solvent drying and recovery devices, and do not cause fire, Since it has the advantages of no pollution to the working environment, it is superior to solvent type adhesives in terms of economic efficiency, pollution prevention, and safety, and its use is rapidly spreading in the adhesive industry. Such hot melt adhesives are generally obtained by blending an tackifying resin with an elastomer but uniformly mixing these components in the absence of a volatile medium such as an organic solvent.

Although hot melt adhesives are used for a wide range of applications, for example, when used in hygienic materials such as paper diapers and hygienic napkins, they have to have a good aesthetic feel and the following characteristics are required.

That is, it should be substantially white or colorless and odorless, have high adhesion to polyethylene film and woven or nonwoven fabrics used in most sanitary materials, and have good coating workability in low temperature area. Melt flow is good even in low temperature region that does not adversely affect the material properties, etc.), the change of color, viscosity, etc. by heating is small, and the cohesive force is large because it is often applied and adhered in the form of thin beads. And other characteristics are required. In particular, in recent years, the appearance of colorless (white), colorless and even odorless adhesive over time is expected.

Conventionally, base resins such as ethylene-vinyl acetate copolymer (EVA), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), tackifying resins and plasticizing oils are prepared. Hot melt adhesives for hygienic materials are known. However, there has yet been known a hot melt adhesive which satisfies all the above-described properties required for sanitary materials and has a long open time, which is a practically important characteristic.

It is therefore an object of the present invention to provide a hot melt adhesive composition that substantially satisfies the properties (especially odorless and colorless or white) required for the above hot melt adhesives for sanitary materials.

That is, the present invention (a) 5 to 25% by weight of styrene-ethylene-butylene-styrene block copolymer (SEBS), (b) hydrogenated aromatic petroleum resin, hydrogenated aliphatic petroleum resin and hydrogenated terpene resin 40 to 70% by weight of at least one tackifying resin, (c) 10 to 40% by weight of the total amount of paraffinic component and naphtanic component in plasticizing oil containing plasticizing oil, and (d) 5 to 5% of liquid rubber 15% by weight and (e) 5 to 10% by weight of a softener composed of an ester bond of a higher monohydric alcohol with fatty acids are provided.

Since (a) SBES used in the present invention is a structure in which an ethylene structure and a butylene structure are mixed in the middle of the terminal styrene polymer block, for example, a styrene having a structure in which a styrene polymer block is bonded to the terminal of the butadiene polymer block. It can be obtained by adding hydrogen to the butadiene polymer portion of the butadiene-styrene (SBS) type block copolymer. The copolymer has a two-phase structure of a styrene phase as a hard block and an ethylene-butylene phase as an elastic block, and usually has a styrene content. The odorless and colorless or white which is 10 to 40 weight% is used.

If the amount of SEBS is small, the heat resistance (at ambient temperature) is poor, and if the amount of SEBS is high, the melt viscosity becomes high and the coating workability is poor. Therefore, 5 to 25% by weight, preferably 7 to 20% by weight, in the adhesive composition of the present invention. More preferably, 7 to 13% by weight.

As a tackifying resin added to improve the flow and coating workability of the adhesive composition, at least one hydrogenated tackifying resin (b) in a hydrogenated aromatic petroleum resin, a hydrogenated aliphatic petroleum resin and a hydrogenated terpene resin Is used. This has a chemical formula in which hydrogen is added to a tackifying resin. It is therefore chemically stable and has little coloration over time.

The tackifying resin (b) is colorless or white and substantially odorless. In particular, hydrogenated aromatic petroleum resins have excellent compatibility with SEBS and excellent heat resistance (at ambient temperature). Specific examples of these resins include, for example, 'Arcon P and Arcon M' of Arakawa Chemical Industries, Ltd. (Japan). (Brand name) is mentioned. The blending amount of the tackifying resin (b) is 40 to 70% by weight, preferably 55 to 65% by weight, because the excess amount of the composition breaks down, the open time becomes short, and the adhesion decreases. . Moreover, it is good to select the thing whose softening temperature is 80-130 degreeC.

Moreover, the plasticizing oil (c) which aims at the fall of a melt viscosity and the provision of flexibility is used for the adhesive composition of this invention. Commercially available plasticized oils are often mixed with paraffinic components, naphthenic components, and aromatic components. However, in the present invention, oils with many paraffinic components and few aromatic components ('flow paraffin' or 'paraffinic') are used. Commercially available as 'oil'. So-called naphthenic oils can also be used, but when the blending amount of the naphthenic components is excessive, coloration and odor are generated in the adhesive composition. Since the aromatic component is compatible with the styrene phase of SEBS to lower the heat adhesion strength, the amount of the aromatic component should be very small.

Since the compounding quantity of the plasticizing oil which concerns on this invention is difficult for the problem of viscosity fall in small quantities, and adhesive force falls in excess, it is good to set the total amount of a paraffin component and a naphthenic component to 10-40 weight% in an adhesive composition.

As the liquid rubber (d) in the present invention, liquid polybutene, liquid polyisobutylene, liquid polybutadiene and the like are suitable.

As the higher monohydric alcohols constituting the ester (e) as a softener in the present invention, specifically, hexyl alcohol, heptyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, nonyl alcohol, decyl alcohol, lauryl alcohol, dodecyl alcohol, beforehand When stil alcohol, pentadecyl alcohol, cetyl alcohol, hepta alcohol, stearyl alcohol, etc., the ester obtained by having 8 to 16 carbon atoms is used as a softener, an adhesive having coordination in cohesion and cohesion can be obtained. When the alcohol has a carbon number of 7 or less, the pressure-sensitive adhesive containing the rosin ester obtained therefrom tends to have insufficient adhesive strength, especially at low temperatures, and when the carbon number 20 or more is used, all three adhesive properties of the adhesive decrease. Tend to be. The higher monohydric alcohols are roughly classified into natural alcohols obtained from natural oils such as palm oil and pine flavored oils and synthetic alcohols obtained from petrochemical industry. The synthetic alcohol is advantageous in that it is inexpensive and mass-produced by, for example, an oxo reaction of a low polymer of α-olefin such as ethylene and propylene. Examples of the synthetic alcohols include Ayadol 115H or 135 (manufactured by Nippon Samreung Kasei Kogyo Co., Ltd., mixed alcohols having 11, 13 and 15 carbon atoms) and Oxocol 1215 (Japan Ilsan Petrochemical Co., Ltd.). And mixed alcohols having 12 to 15 carbon atoms.

As fatty acids which are esterified with the higher monohydric alcohols, various kinds such as monomerized fatty acid, dimerized fatty acid, trimerized fatty acid and multimerized fatty acid can be used, but the use of high-purity dimerized fatty acid through distillation operation good. The content of dimerized fatty acid is preferably about 90% or more, preferably 95% or more.

The esterification reaction of the higher monohydric alcohols with dimerized fatty acids can be carried out according to various known methods, and for example, both can be obtained by heating them under a temperature condition of about 180 to 300 ° C for 2 to 10 hours. .

The ester softener (e) thus obtained usually has a yellow or brown transparent liquid to balsam phase appearance, and an acid value of about 15 or less is good or less.

According to the present invention, wax may be added and used within 10% by weight as needed, and preferred waxes include paraffin wax. In the present invention, it is also preferable to add 0.05 to 2% by weight of UV absorber, preferably 0.1 to 0.5% by weight, in order to improve heat stabilizer, especially phenolic heat stabilizer and fluorescence removal light resistance.

The hot melt adhesive composition of the present invention is white or colorless due to the above-mentioned constitution and has no coloring over time and is substantially odorless. In addition, the adhesive composition of the present invention can be applied to a polyethylene film and a woven or nonwoven fabric in a bead form, and furthermore, has flexibility at an ambient temperature after adhesion, and therefore is particularly suitable for sanitary materials such as paper diapers and sanitary nerfs, especially for paper diapers. Most suitable.

Moreover, the adhesive composition of the present invention has a low melt viscosity, good viscosity stability and long open time, so that workability of the coating process to the adherend and the bonding process is good. An example is given and described below.

In the following examples, parts simply referred to as parts by weight, and the characteristic test was in accordance with the following measurement method.

Sticky

Measured by J. Dow method at 0 ° C or 20 ° C.

Adhesion

A 25-mm-wide polyester film coated with each adhesive sample and K-liner (basic weight 240 g / m 2) were combined to measure a 180-degree peeling load at a speed of 300 mm / min as an Instron meter.

cohesion

The polyester film of width 25mm which apply | coated each adhesive sample was created, this test piece was affixed on the same K-liner of 25mmX25mm area mentioned above, and the distance which slipped by creep test by PSTC-7 is measured.

The specific ester preparation example is shown as a reference example as a softener component, and the preparation example is then shown as an example by the adhesive agent of this invention.

[Reference Example]

500 parts of a commercially available dimerized fatty acid of 196 (Union Camp Co., UNIDYME 14, 96% of dimerized fatty acid) and 389 parts of synthetic alcohol (a mixture of 58% tridecyl alcohol and 42% pentadecyl alcohol) were added to the reactor. After heating for 4 hours at 260 to 270 ° C. in a noble gas atmosphere, the mixture is kept warm for 30 minutes under reduced pressure. The acid value of the product was 5.9, the color tone (Gardner number) was 8, and the viscosity (25 ° C) was 680 cps.

Let this be ester A.

Example 1

10 parts of SEBS (Shell Chemical, Creton G1652, styrene content 29%), 25 parts of paraffinic oil (Exxon Chemical Fluid Paraffin, Cristol # 352, 99% or more of paraffin components), hydrogenated aromatic petroleum resin (Arakawa Chemical) (Japan), Arcon P-100, fully hydrogenated product, softening temperature 10 ℃) by ventilating method, 10 parts of liquid polybutene (Japan polybutene 300R), UV absorber (Shibagai Co., Ltd., T 0.3 parts of nubin P) and 7 parts of ester A were heated and melted at about 160 ° C. to obtain a hot melt composition. The properties of this adhesive are shown in Table 1.

Example 2

15 parts of SEBS (manufactured by Shell Chemicals, Creton G1650, 28% styrene content, 5 parts and 14% Creton G1657 styrene content, 10 parts), 15 parts of Cristol # 352, 55 parts of Arcon P-100, liquid polybutene 10 parts of petrochemical (Japan) polybutene 300R), 5 parts of wax (manufactured by Japan, Parispin wax 135 ° F), 0.3 parts of UV absorbers (Shibagaiki Co., Tinuvin P) and 7 parts of ester A at about 130 to 180 ° C. It heated and melted and obtained the adhesive composition. The properties of this adhesive are shown in Table 1.

[Examples 3 to 5]

As in Example 2, but using the composition shown in Table 1 to obtain a hot melt adhesive. The characteristics are also shown in Table 1.

[Comparative Examples 1-7]

As in Example 2, but a hot melt adhesive was obtained according to the composition shown in Table 2. The characteristics are also shown in Table 2. As the aromatic petroleum resin, Samjeong Petrochemical Co., Ltd. (Japan) FTR-6100 was used as the terpene-based resin, and Ansan Oil Retainer (Japan) Ys resin Px-1000 was used.

* Styrene-isoprene-styrene block copolymer made from shell chemicals, Carriprex TR1107

* Made in Japan, styrene-butadiene-styrene block copolymer, tauprene A

* Chemical Hysol SAS-LH, more than 99% of aromatic components

Claims (1)

(a) 5 to 25% by weight of styrene-ethylene-butylene-styrene block copolymer (SEBS), (b) at least one of hydrogenated aromatic petroleum resins, hydrogenated aliphatic petroleum resins, and hydrogenated terpene resins. 40 to 70 wt% of the tackifying resin, (c) 10 to 40 wt% of the total amount of paraffinic and naphthenic components in the plasticizing oil containing plasticizing oil, (d) 5 to 15 wt% of the liquid rubber, and (e) A hot melt adhesive composition for sanitary materials, comprising 5 to 10% by weight of a softener.