High resilience hot melt film based on SEBS modification and preparation method thereof

Abstract

The application discloses a high-resilience hot-melt film based on SEBS modification and a preparation method thereof. The high-resilience hot-melt film comprises, according to mass percentage, 45-65% of a high-styrene-content high-molecular-weight SEBS base material, 20-45% of a plasticizer, 5-25% of an adhesion-improving resin and 1-10% of a poly-alpha-methylstyrene resin, the content of styrene in the SEBS base material is greater than 35%, and the molecular weight is greater than 200,000. The application adopts the above high-resilience hot-melt film based on SEBS modification and the preparation method thereof, the SEBS base material has high molecular weight and high styrene content, the adhesion-improving agent and the plasticizer are less used, raw materials are easy to blend, the hot-melt adhesive particles can be mixed by a common mixer and then extruded and granulated by an extruder, the hot-melt film is prepared by a casting machine, the prepared hot-melt film has better resilience, low pressure sensitivity, no self-adhesion, and the like, and can be applied to underwear fabrics to enhance the resilience of the application part and provide support, and meanwhile, the hot-melt film is soft and does not affect the hand feeling.

Description

Technical Field

[0001] This invention relates to the field of hot melt film technology, and in particular to a high resilience hot melt film based on SEBS modification and its preparation method. Background Technology

[0002] Most underwear fabrics are made of highly elastic materials, offering advantages such as good stretchability, light weight, and strong moisture absorption. Hot melt film can be cut into different sizes according to actual needs and has strong adhesion, allowing it to replace sewing when applied to the seams of underwear fabrics. Currently, ordinary hot melt film used for underwear fabrics lacks sufficient elasticity. When underwear fabrics are subjected to elastic stretching and deformation, ordinary hot melt film exhibits poor stretchability, high pressure sensitivity, and a tendency to self-adhere, affecting the comfort of the underwear and shortening its lifespan.

[0003] Chinese patent CN115895539A discloses a high-resilience hot melt adhesive, its preparation method, and its application. This patent uses a combination of high-molecular-weight and low-molecular-weight SEBS, liquid petroleum resin and hydrogenated petroleum resin as tackifiers, paraffin oil, naphthenic oil, and aromatic oil as plasticizers, and poly-α-methylstyrene resin to improve heat resistance. Antioxidants are also added. The mixture is melt-blended in a reaction vessel, cooled, and dried to produce the hot melt adhesive. The patent further protects the elastic composite fabric prepared using this hot melt adhesive. However, this patent does not produce a film, nor does it test its adhesive properties.

[0004] The disadvantages of the above-mentioned hot melt adhesive are:

[0005] 1. The liquid petroleum resin used is difficult to mix and needs to be heated and melted in a reaction vessel. After cooling, it is in block form and cannot be used directly by ordinary casting machines to cast into a film.

[0006] 2. The proportion of liquid petroleum resin and hydrogenated petroleum resin used for thickening is very high, resulting in hot melt adhesive with strong pressure sensitivity and easy self-adhesion.

[0007] 3. The addition of low molecular weight SEBS and a high amount of tackifying resin affect the resilience of the hot melt adhesive.

[0008] Therefore, there is an urgent need to develop a hot melt film with high resilience, good adhesion, and low self-adhesion. Summary of the Invention

[0009] The purpose of this invention is to provide a high-resilience hot melt film based on SEBS modification and its preparation method, so as to solve the problems of low resilience and high self-adhesion of the above-mentioned hot melt film. This invention aims to prepare a high-resilience, low-pressure-sensitive hot melt adhesive to enhance the resilience of the application area and provide support, while being soft and not affecting the feel.

[0010] To achieve the above objectives, the first aspect of the present invention provides a high resilience hot melt film based on SEBS modification, wherein the high resilience hot melt film comprises, by weight percentage, 45-65% high molecular weight SEBS base material with high styrene content, 20-45% plasticizer, 5-25% tackifying resin and 1-10% polyα-methylstyrene resin.

[0011] Preferably, the styrene content in the SEBS base material is greater than 35%, and the molecular weight is greater than 200,000.

[0012] Preferably, the SEBS base material is Kronen A1536, with a molecular weight greater than 200,000 and a styrene content of 42%.

[0013] Too low a styrene content will affect resilience, while too high a content will affect adhesion.

[0014] Preferably, the plasticizer is low-viscosity paraffin oil.

[0015] Preferably, the plasticizer is 10# paraffin oil.

[0016] Preferably, the tackifying resin is a copolymer of fully hydrogenated DCPD and hydrogenated C9 DCPD, with a softening point of 90-120°C.

[0017] Preferably, the tackifying resin is ExxonMobil Escorez 5300.

[0018] Preferably, the softening point of poly-α-methylstyrene resin is 90-110℃.

[0019] A second aspect of this invention provides a method for preparing a high-resilience hot melt film based on SEBS modification, comprising the following steps:

[0020] S1: Mix SEBS base material and plasticizer evenly to obtain oil-extended SEBS;

[0021] S2: Mix oil-extended SEBS, tackifying resin, and polyα-methylstyrene resin evenly to obtain a blend;

[0022] S3: The blend is extruded and granulated using a twin-screw extruder;

[0023] S4: The obtained particles are fed into a casting machine to form a hot melt film.

[0024] Preferably, the mixing temperature in step S1 is 40-60°C; the mixing temperature in step S2 is room temperature.

[0025] Preferably, the extrusion temperature of the twin-screw extruder in step S3 is 130-170℃, and the casting temperature of the casting machine in step S4 is 150-180℃.

[0026] Therefore, the present invention provides a high-resilience hot melt film based on SEBS modification with the above-mentioned structure and its preparation method, which has the following beneficial effects:

[0027] (1) The hot melt adhesive of the present invention uses less tackifier, does not require the addition of low molecular weight SEBS, and the SEBS used has a high molecular weight and high styrene content, so it has better resilience, low pressure sensitivity, and does not self-adhere, which affects its use.

[0028] (2) The tackifier of the present invention does not use liquid resin, which is difficult to mix. All materials used are easy to mix and can be mixed by ordinary mixer and then put into extruder for granulation. The hot melt adhesive particles are cast into film by casting machine.

[0029] (3) This invention achieves low surface viscosity of the hot melt film by selecting low-viscosity paraffin oil and hydrogenated DCPD, and obtains good adhesion performance by controlling the ratio of plasticizer to tackifier. Therefore, the selection and ratio adjustment of SEBS, plasticizer, tackifying resin and additives result in a hot melt film with good resilience and low surface viscosity.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0032] The present invention will be further described below. It should be noted that this embodiment is based on the present technical solution and provides detailed implementation methods and specific operation processes, but the present invention is not limited to this embodiment.

[0033] The raw material composition of the examples and comparative examples is shown in Table 1.

[0034] Table 1 Raw Material Composition Table

[0035]

[0036] In Table 1, SEBS is Kraton A1536, the tackifying resin is ExxonMobil Escorez 5300, and the softening point of poly-α-methylstyrene resin is 100℃.

[0037] Comparative Example 1 is Example 2 in which SEBS is replaced with Yuehua YH602T (35% styrene content, 220,000 molecular weight); Comparative Example 2 is Example 2 in which the proportion of tackifying resin is increased to 30%; Comparative Example 3 is Example 2 in which oil is replaced with relatively high viscosity 46# paraffin oil; Comparative Example 4 is Example 2 in which poly-α-methylstyrene resin is increased to 15%; Comparative Example 5 is Example 2 in which poly-α-methylstyrene resin is not added.

[0038] The preparation methods for the examples and comparative examples are as follows:

[0039] SEBS base material and plasticizer were mixed at low speed at 50°C for 30 minutes and then allowed to stand for at least 4 hours. Oil-extended SEBS was then mixed with tackifying resin and polyα-methylstyrene resin at high speed at room temperature for 3 minutes. After the materials were mixed, they were extruded and granulated using a twin-screw extruder at an extrusion temperature of 155°C. The resulting particles were then fed into a casting machine to cast a film at a casting temperature of 165°C to obtain a hot melt film.

[0040] Test case

[0041] The performance of the hot melt films prepared in the examples and comparative examples was tested.

[0042] (1) The rebound performance of 300% at constant elongation refers to FZ / T 75004-2014. Take a hot melt film with a length of 10cm, a width of 1cm and a thickness of 0.5mm, stretch it to 40cm at 500mm / min, repeat 10 times, and then let it rest horizontally for 5min. Measure the length L of the sample. The rebound rate = 100% - (L-10) / 10×100%.

[0043] (2) Adhesion performance refers to GB / T 2791. Take a hot melt film with a length of 10cm, a width of 1cm and a thickness of 0.5mm, press it at 150℃ and 0.4Mpa for 25 seconds, and after cooling at room temperature, test the peel force on a tensile tester at a tensile speed of 200mm / min.

[0044] (3) Self-adhesion test: Take a hot melt film with a length of 10cm, a width of 1cm and a thickness of 0.5mm, fold it from one end 1cm and measure the recovery time.

[0045] The test results are shown in Table 2.

[0046] Table 2 Performance Test Results

[0047]

[0048] As can be seen from Table 2, Examples 1-3 can simultaneously ensure high resilience, high peel strength, and short self-adhesion recovery time of the hot melt film. Comparative Example 1, using Yuehua YH602T as the SEBS base material, reduced styrene content and resulted in poor adhesion. Comparative Example 2 increased the proportion of tackifying resin, which improved the adhesion of the hot melt film, but significantly prolonged the self-adhesion recovery time, leading to severe self-adhesion. Comparative Example 3 used high-viscosity 46# paraffin oil, which improved peel strength and adhesion of the hot melt film, but significantly prolonged the self-adhesion recovery time. Comparative Example 4 increased the content of poly-α-methylstyrene resin, which increased the smoothness of the film surface, reduced surface tack, and shortened the self-adhesion recovery time, but decreased its resilience. Comparative Example 5 removed the addition of poly-α-methylstyrene resin, resulting in a prolonged self-adhesion recovery time. These comparative examples demonstrate that the raw material composition and addition amount in this invention maintain the various properties of the hot melt film at a high level, making it suitable for application in highly elastic fabrics such as underwear.

[0049] Therefore, this invention provides a high-resilience hot melt film based on SEBS modification and its preparation method, using the above-mentioned structure. The SEBS base material used has a high molecular weight and high styrene content, and uses less tackifier and plasticizer. The raw materials are easy to blend and can be mixed by a conventional mixer and then extruded and granulated by an extruder. The hot melt adhesive particles are then cast into a film by a casting machine. The prepared hot melt film has better resilience, low pressure sensitivity, and does not self-adhere, thus not affecting its use. When applied to underwear fabrics, it can enhance the resilience of the application area and provide support, while remaining soft and not affecting the feel.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-resilience hot melt film based on SEBS modification, characterized in that: The high-resilience hot melt film is composed of the following components by weight percentage: 45-65% high-molecular-weight SEBS base material with high styrene content, 20-45% plasticizer, 5-25% tackifying resin, and 1-10% poly-α-methylstyrene resin; The styrene content in SEBS base material is greater than 35%, and the molecular weight is greater than 200,000; The plasticizer is No. 10 paraffin oil; The tackifying resin is a copolymer of fully hydrogenated DCPD and hydrogenated C9 DCPD, with a softening point of 90-120℃.

2. The high resilience hot melt film based on SEBS modification according to claim 1, characterized in that: The tackifying resin is ExxonMobil Escorez 5300.

3. The high resilience hot melt film based on SEBS modification according to claim 1, characterized in that: The softening point of poly-α-methylstyrene resin is 90-110℃.

4. A method for preparing a high-resilience hot melt film based on SEBS modification according to any one of claims 1-3, characterized in that: Includes the following steps: S1: Mix SEBS base material and plasticizer evenly to obtain oil-extended SEBS; S2: Mix oil-extended SEBS, tackifying resin, and polyα-methylstyrene resin evenly to obtain a blend; S3: The blend is extruded and granulated using a twin-screw extruder; S4: The obtained particles are fed into a casting machine to form a hot melt film.

5. The method for preparing a high-resilience hot melt film based on SEBS modification according to claim 4, characterized in that: The mixing temperature in step S1 is 40-60℃; the mixing temperature in step S2 is room temperature.

6. The method for preparing a high-resilience hot melt film based on SEBS modification according to claim 4, characterized in that: In step S3, the extrusion temperature of the twin-screw extruder is 130-170℃, and in step S4, the casting temperature of the casting machine is 150-180℃.

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