Hot melt composition

Abstract

To provide a hot melt composition which has high productivity because it is suitable for spray coating, hardly causes phase separation during melting, suppresses surface tack after solidification, and has good weather resistance because it is excellent in wet heat resistance.SOLUTION: The hot melt composition comprises a styrene-based thermoplastic elastomer (A) having a styrene content of ≤ 18 wt.%, an amorphous polyalphaolefin (B), and a tackifier (C).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hot melt composition. [Background technology]

[0002] Hot melt compositions have been the subject of extensive research and development. Hot melt compositions melt when heated and solidify when cooled to room temperature (approximately 23°C), making them ideal for use as adhesives. Their characteristics include being solvent-free, environmentally friendly, solidifying in a short time, and being extremely easy to handle. They are also widely used in a variety of fields because they can improve the working environment at manufacturing sites.

[0003] Previously, the applicant of the present application invented a hot melt composition comprising an amorphous polyalphaolefin (A), a styrene-based thermoplastic elastomer (B), and a tackifier (C), wherein the amorphous polyalphaolefin (A) has a melt viscosity (190°C) of 5,000 to 300,000 mPa·s and a tensile strength of 2.3 to 6.0 MPa (Patent Document 1). This hot melt composition maintained its conventional strength while also exhibiting adhesive strength to materials other than olefin-based materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-021014

[0005] Generally, when building a wooden house, a moisture-permeable waterproof sheet is placed between the exterior and interior materials to prevent rain from leaking through the walls and to allow moisture generated by the temperature difference between the inside and outside of the house to escape.

[0006] In recent years, hot-melt compositions have been used in the manufacturing process of moisture-permeable waterproof sheets due to their excellent adhesive stability at room temperature. To manufacture moisture-permeable waterproof sheets, the hot-melt composition is applied to a nonwoven fabric substrate using a so-called curtain spray method, followed by lamination of a porous film. The sheet is then left to solidify at room temperature, rolled up, and transported to the construction site for installation. Curtain spraying is a highly efficient method for thinly applying a coating to a large area, making it ideal for manufacturing moisture-permeable waterproof sheets. Therefore, hot-melt compositions have been required to have properties suitable for curtain spraying, such as excellent spray applicability and resistance to phase separation upon melting. Furthermore, to prevent adhesion to the backside of the moisture-permeable waterproof sheet during winding, it has been required to suppress surface tack after solidification. Furthermore, since moisture-permeable waterproof sheets are installed directly next to exterior materials, they also require good weather resistance, especially in high-temperature and humid environments, leaving room for improvement. Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a hot melt composition that is suitable for spray application and therefore has high productivity, is less likely to cause phase separation when melted, has reduced surface tack after solidification, and has excellent wet heat creep resistance and therefore has good weather resistance. [Means for solving the problem]

[0008] The present invention is a hot melt composition characterized by containing a styrene-based thermoplastic elastomer (A) having a styrene content of 18% by weight or less, an amorphous polyalphaolefin (B), and a tackifier (C). [Effects of the Invention]

[0009] The hot melt composition of the present invention is suitable for spray application, which allows for high productivity, and is less likely to cause phase separation during melting, and has the effect of suppressing surface tack after solidification. It also has excellent resistance to moist heat creep and therefore good weather resistance. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Styrene-based thermoplastic elastomer> In the present invention, a styrene-based thermoplastic elastomer (A) having a styrene content of 18% by weight or less is used, and this component (A) is used as the base polymer of the hot melt composition according to the present invention.

[0011] Styrenic thermoplastic elastomers are composed of hard blocks derived from styrene compounds and soft blocks derived from diene compounds. The bonding configuration of each block can be linear, branched, or radial, but linear ones are relatively common.

[0012] Styrenic thermoplastic elastomers are divided into "unhydrogenated styrenic thermoplastic elastomers" in which the soft blocks are not hydrogenated, and "hydrogenated styrenic thermoplastic elastomers" in which the soft blocks are hydrogenated.

[0013] Examples of unhydrogenated styrene-based thermoplastic elastomers include styrene-isoprene-styrene block copolymers (SIS) and styrene-butadiene-styrene block copolymers (SBS).

[0014] Examples of hydrogenated styrene-based thermoplastic elastomers include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene / propylene-styrene block copolymer (SEEPS).

[0015] In the present invention, among these, it is preferable to use a hydrogenated styrene-based thermoplastic elastomer because of its excellent adhesive stability, and it is particularly preferable to use a styrene-ethylene / butylene-styrene block copolymer (SEBS) or a styrene-ethylene / propylene-styrene block copolymer (SEPS).

[0016] In styrene-based thermoplastic elastomers, hot melt compositions with various properties can be produced by appropriately adjusting the proportions of the hard block and the soft block. Generally, a higher hard block proportion tends to increase rigidity, while a lower hard block proportion tends to increase flexibility.

[0017] In the present invention, the styrene content of the component (A) must be 18% by weight or less, preferably 1 to 17% by weight, more preferably 3 to 16% by weight, and particularly preferably 5 to 15% by weight.

[0018] The inventors of the present invention have found that when the styrene content of component (A) is within the above range, the spray applicability of the hot melt composition of the present invention is improved. One of the factors that contributes to this effect is presumed to be that by keeping the styrene content somewhat low, compatibility with the other components is improved, allowing the hot melt composition to be sprayed efficiently during spray application.

[0019] The blending ratio of the (A) component is preferably 5 to 35 parts by weight, more preferably 8 to 30 parts by weight, and particularly preferably 10 to 25 parts by weight, per 100 parts by weight of the total of the (A) to (C) components.

[0020] Specific examples of the component (A) include GLOBALPRENE 9557D (trade name, manufactured by LCY, styrene-ethylene / butylene-styrene block copolymer (SEBS), bond type: linear, styrene content: 13% by weight).

[0021] <Amorphous polyalphaolefin> In the present invention, an amorphous polyalphaolefin (B) is used. The component (B) is an amorphous olefin-based polymer.

[0022] The structure of component (B) preferably contains propylene as a structural unit. Specific examples include propylene homopolymers, as well as copolymers or terpolymers of propylene with a monomer selected from ethylene, 1-butene, and 1-hexene. Among these, propylene homopolymers and propylene-ethylene copolymers are preferred because of their high stability and ease of handling.

[0023] The inventors of the present invention have found that the use of component (B) improves the wet heat creep resistance of the hot melt composition of the present invention. One of the factors contributing to this effect is believed to be the improved cohesive strength of the entire system due to the use of component (B). It is also believed that component (B) has good compatibility with component (A), which tends to improve wettability to substrates during spray application.

[0024] The melt viscosity (190°C) of the component (B) is preferably 500 to 60,000 mPa·s, more preferably 800 to 30,000 mPa·s, and particularly preferably 1,000 to 10,000 mPa·s.

[0025] The softening point of the component (B) is preferably 90 to 160° C., more preferably 95 to 155° C., even more preferably 100 to 150° C., and particularly preferably 105 to 145° C. If the softening point is within this range, the hot melt composition tends to have both good heat resistance and spray applicability.

[0026] The blending ratio of the (B) component is preferably 5 to 50 parts by weight, more preferably 8 to 45 parts by weight, and particularly preferably 10 to 40 parts by weight, per 100 parts by weight of the total of the (A) to (C) components.

[0027] Specific examples of component (B) include RT2535 (trade name, manufactured by Rextack, amorphous polyalphaolefin (propylene-ethylene copolymer), melt viscosity (190°C): 3,500 mPa·s, softening point: 132°C), Aerafin 17 (trade name, manufactured by Eastman, amorphous polyalphaolefin (propylene-based polymer), melt viscosity (190°C): 1,500 mPa·s, softening point: 125°C), and RT2385 (trade name, manufactured by Rextack, amorphous polyalphaolefin (propylene-ethylene copolymer), melt viscosity (190°C): 8,500 mPa·s, softening point: 141°C).

[0028] <Tackifier> The present invention uses a tackifier (C), and examples of the component (C) include terpene resins, terpene phenol resins, rosin resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, alicyclic hydrocarbon resins, and hydrogenated or modified products thereof.

[0029] The softening point of the component (C) is preferably from 60 to 250°C, more preferably from 70 to 200°C, and particularly preferably from 80 to 180°C.

[0030] The blending ratio of the (C) component is preferably 35 to 80 parts by weight, more preferably 40 to 75 parts by weight, and particularly preferably 45 to 70 parts by weight, per 100 parts by weight of the total of the (A) to (C) components.

[0031] Specific examples of the component (C) include YS Resin PX1250 (trade name, manufactured by Yasuhara Chemical Co., Ltd., terpene resin, softening point: 120°C to 130°C), Tamanor 803L (trade name, manufactured by Arakawa Chemical Industries, Ltd., terpene phenol resin, softening point: 145°C to 160°C), Pine Crystal KR-85 (trade name, manufactured by Arakawa Chemical Industries, Ltd., rosin resin, softening point: 80°C to 87°C), YL120 (trade name, manufactured by Yuen Liang Industrial Co., Ltd., aromatic hydrocarbon resin, softening point: 115°C to 125°C), Escorez 5380 (trade name, manufactured by ExxonMobil, alicyclic hydrocarbon resin, softening point: 80°C to 90°C), H5-1001 (trade name, manufactured by Henghe Co., Ltd., aliphatic hydrocarbon resin, softening point: 95°C to 105°C), and T-REZ HA125 (trade name, manufactured by ENEOS Corporation, hydrogenated alicyclic hydrocarbon resin, softening point: 120°C to 130°C) is an example.

[0032] <Crystalline olefin elastomer> In addition to the above components (A) to (C), the present invention can also use a crystalline olefinic elastomer (D). Component (D) can be, for example, a copolymer of an olefinic monomer produced using a metallocene catalyst. Specific examples include ethylene-propylene copolymers and ethylene-octene copolymers.

[0033] Use of component (D) slightly improves the wettability of the substrate when sprayed, and also slightly reduces surface tackiness after solidification, which tends to improve handling.

[0034] The blending ratio of the (D) component is preferably 1 to 100 parts by weight, more preferably 2 to 50 parts by weight, and particularly preferably 3 to 30 parts by weight, per 100 parts by weight of the total of the (A) to (C) components.

[0035] Specific examples of component (D) include Vistamaxx 8880 (trade name, manufactured by ExxonMobil, crystalline olefin elastomer (propylene-ethylene copolymer, ethylene content: 6% by weight), melt viscosity (190°C): 1,200 mPa·s).

[0036] <Other ingredients> In addition, in the present invention, a plasticizer or wax may be used. By using these components, the melt viscosity can be easily adjusted within an appropriate range, which tends to further improve workability.

[0037] Examples of plasticizers include organic compounds that are fluid at room temperature (23°C). Types of plasticizers include paraffinic oil, naphthenic oil, polybutene, polyisobutylene, and liquid paraffin. Among these, polybutene and polyisobutylene are preferred because they are highly stable and easy to handle.

[0038] Specific examples of plasticizers include Nippon Oil Polybutene HV-100 (trade name, manufactured by ENEOS Corporation, polybutene, number average molecular weight: 980) and PB-950 (trade name, manufactured by Daelim Corporation, polybutene, number average molecular weight: 930).

[0039] Waxes include natural waxes and synthetic waxes. Natural waxes include paraffin wax and microcrystalline wax, and synthetic waxes include polyethylene wax and polypropylene wax.

[0040] Specific examples of waxes include Hiwax NP500 (trade name, manufactured by Mitsui Chemicals, Inc., polypropylene wax, melting point: 161°C), H-503 (trade name, manufactured by Qingdao Sinoplas Hi-New Material Co., Ltd., polypropylene wax, melting point: 146°C), and Umex 1010 (trade name, manufactured by Sanyo Chemical Industries, Ltd., maleic anhydride-modified polypropylene wax, melting point: 135°C).

[0041] In the present invention, an antioxidant may be used as an additive. Examples of the antioxidant include phosphites, naphthylamines, p-phenylenediamines, quinolines, hydroquinones, bis-tris-polyphenols, thiobisphenols, and hindered phenols, and these may be used alone or in combination.

[0042] Specific examples of antioxidants include Sumilizer GP (trade name, manufactured by Sumitomo Chemical Co., Ltd.), Songnox 1010 (trade name, manufactured by Songwon Co., Ltd.), and Chinox 1010 (trade name, manufactured by Double Bond Chemical Co., Ltd.).

[0043] In the present invention, various additives such as fillers such as calcium carbonate, talc, and clay, preservatives, and colorants may also be contained.

[0044] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these descriptions. [Example]

[0045] <Examples and Comparative Examples> The hot melt compositions according to the examples and comparative examples were produced by thoroughly kneading the ingredients in the formulation shown in Table 1 in a flask adjusted to 180°C. Here, the numerical values ​​in Table 1 represent parts by weight. The raw materials used are shown below. GLOBALPRENE 9557D (product name, manufactured by LCY, styrene-ethylene / butylene-styrene block copolymer (SEBS), bond type: linear, styrene content: 13% by weight) GLOBALPRENE 9552U (product name, manufactured by LCY, styrene-ethylene / butylene-styrene block copolymer (SEBS), bond type: linear, styrene content: 30% by weight) RT2535 (trade name, manufactured by Rextack, amorphous polyalphaolefin (propylene-ethylene copolymer), melt viscosity (190°C): 3,500 mPa·s, softening point: 132°C) Aerafin 17 (trade name, manufactured by Eastman, amorphous polyalphaolefin (propylene-based polymer), melt viscosity (190°C): 1,500 mPa·s, softening point: 125°C) RT2385 (trade name, manufactured by Rextack, amorphous polyalphaolefin (propylene-ethylene copolymer), melt viscosity (190°C): 8,500 mPa·s, softening point: 141°C) Escorez 5380 (trade name, manufactured by Exxon, tackifier (alicyclic hydrocarbon resin), softening point: 80-90°C) H5-1001 (trade name, manufactured by Henghe Co., Ltd., tackifier (aliphatic hydrocarbon resin), softening point: 95 to 105°C) Vistamaxx 8880 (trade name, ExxonMobil, crystalline olefin-based elastomer (propylene-ethylene copolymer, ethylene content: 6% by weight), melt viscosity (190°C): 1,200 mPa·s) Affinity GA1900 (trade name, manufactured by Dow, crystalline olefin-based elastomer, melt viscosity (177°C): 8200 mPa·s) PB-950 (trade name, manufactured by Daelim, polybutene) PB-1300 (product name, manufactured by Daelim, polybutene) H-503 (product name, manufactured by Qingdao Sinoplas Hi-New Material Co., Ltd., polypropylene wax, melting point: 146°C) Songnox 1010 (product name, manufactured by Songwon, antioxidant)

[0046] [Table 1]

[0047] The hot melt compositions produced in the above examples were evaluated for various physical properties in the following manner. The results are shown in Table 2.

[0048] <Spray application> 50 g of the hot melt composition was charged into a hot melt gun set at 180°C and maintained at this temperature for 1 hour until it was completely melted. Then, a coating amount of 3 g / m was applied to a PET film (30 cm x 20 cm). 2 The appearance after application was visually observed based on the following evaluation criteria. Application form: When the application was performed uniformly in a fiber shape, it was evaluated as ◯, and when the spray was unstable and the application was uneven, it was evaluated as ×. Wetting of substrate: Immediately after spray application, the coating showed very good wetting of the PET substrate, was evaluated as ⊚, good wetting, and poor wetting, as x.

[0049] <compatibility> 10 g of the hot melt composition was placed in a 30 ml standard bottle and left to stand in a thermostatic chamber adjusted to 180°C for 24 hours, then removed and visually inspected for the presence or absence of phase separation. A homogeneous composition without phase separation was evaluated as ◯, and a composition with phase separation was evaluated as ×.

[0050] <Heat and humidity creep resistance> Using a hot melt gun set at 180°C, apply 3g / m to a B-flute cardboard (10cm x 2.5cm). 2 A hot melt composition was applied in a bead shape using a pressure-sensitive adhesive, and a cardboard sheet was placed on top and pressed with a 1 kg load for 2 seconds to prepare a test piece. The test piece was cured at 23°C for 24 hours and then left to stand for 30 minutes in a thermostatic chamber adjusted to a temperature of 60°C and a humidity of 90%, after which a 300 g weight was attached to one side and the time until the weight fell was measured. Test pieces that took 100 minutes or more to fall were evaluated as ○, and those that took less than 100 minutes were evaluated as ×.

[0051] <Surface tackiness> 20 g of the hot melt composition was placed in a metal can and allowed to stand in a thermostatic chamber adjusted to 180°C. After complete melting, the composition was removed, dropped onto smooth release paper, and cured at 23°C for 24 hours. The surface of the solidified hot melt was then pressed firmly with a finger, and the sensation felt when released was evaluated by sensory evaluation. A rating of ⊚ was given for no feeling left on the finger and almost no stickiness, a rating of ◯ for a slight feeling of sticking to the finger, and a rating of × for a strong stickiness.

[0052] [Table 2]

[0053] When hot melt compositions according to the examples were produced using various styrene-based thermoplastic elastomers, the results showed that they were suitable for spray application, which resulted in high productivity, less phase separation during melting, less surface tack after solidification, and excellent weather resistance due to their excellent moist heat creep resistance.

[0054] In particular, comparing Example 1 with Comparative Example 1, the spray applicability and moist heat creep resistance were found to differ depending on whether or not the amorphous polyalphaolefin (B) was blended. Also, comparing Example 4 with Comparative Example 2, the spray applicability and compatibility were found to differ depending on the styrene content of the styrene-based thermoplastic elastomer.

Claims

1. A hot melt composition comprising: a styrene-based thermoplastic elastomer (A) having a styrene content of 18% by weight or less; an amorphous polyalphaolefin (B); and a tackifier (C).

2. 2. The hot melt composition according to claim 1, wherein the amorphous polyalphaolefin (B) has a softening point of 90 to 160°C.

3. 2. The hot melt composition according to claim 1, further comprising a wax.

4. 2. The hot melt composition according to claim 1, further comprising a crystalline olefinic elastomer (D).

5. 5. The hot melt composition according to claim 1, which is used for a moisture-permeable waterproof sheet.

6. A moisture-permeable waterproof sheet coated with the hot melt composition according to any one of claims 1 to 4.

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