A defluorescent pressure-sensitive hot melt adhesive and its preparation process

Abstract

The present invention relates to D06N3, and more specifically, to a defluorescent pressure-sensitive hot melt adhesive and a preparation process thereof. The raw materials of the defluorescent pressure-sensitive hot melt adhesive include styrene polymers, softeners, tackifiers, antioxidants and fluorescent absorbers. By controlling the proportion of each substance in the hot melt adhesive, 20-45 parts by weight of styrene polymers, 25-45 parts by weight of softeners, 25-50 parts by weight of tackifiers, 0.05-2 parts by weight of antioxidants and 2-4 parts by weight of fluorescent absorbers are compounded, so that the viscosity and moisture resistance of the hot melt adhesive are improved, and the production process of the hot melt adhesive used in diapers is further simplified. When producing the composite core of the diaper, the pressure-sensitive hot melt adhesive, non-woven fabrics and SAP can be bonded together by the pressure of the fingers, which significantly reduces the cost in the production process of the diaper core and improves production efficiency.

Description

Technical Field

[0001] The present invention relates to D06N3, and more specifically, to a defluorescent pressure-sensitive hot melt adhesive and a preparation process thereof. Background Art

[0002] With the development of modern society, diapers have become a major consumable in maternal and child products. Compared with diapers, diapers are less likely to breed bacteria. The core is the core part of diapers, and the quality of the core directly determines the quality of diapers. The core can be divided into two types. One is a core mixed with fluff pulp and high molecular absorbent resin (SAP); the other is a composite core that uses hot melt adhesive to fix dust-free paper or non-woven fabric and SAP in layers.

[0003] Patent No. CN103614111B provides a urine-coloring hot melt adhesive for diapers. By controlling the melt index of the acrylic terpolymer to be greater than 5g / 10min and the acrylic acid content in the copolymer to be 20-40wt%, the prepared hot melt adhesive changes color quickly after contacting water, and the color is bright. Patent No. CN110205065B provides an elastic hot melt pressure-sensitive adhesive and its preparation method and application. The addition of modifier polybutadiene and a specific proportion of cyclohexane oil, white oil or low molecular weight polybutadiene improves the elastic recovery rate of the hot melt adhesive. It is applied to the elastic material part of diapers and has excellent tensile properties.

[0004] For the composite core, hot melt adhesive is needed to bond and fix each core layer. However, the adhesive used for the core of this diaper has poor viscosity when it comes into contact with water, resulting in poor water absorption strength of the diaper. When babies wear diapers at night, the urine produced is stored in the diaper, which impairs the performance of the diaper and causes urine leakage. Summary of the invention

[0005] In order to solve the above problems, the first aspect of the present invention provides a defluorescent pressure-sensitive hot melt adhesive, the raw materials of which include a styrene polymer, a softener, a tackifier, an antioxidant and a fluorescent absorber.

[0006] As a preferred technical solution of the present invention, the styrene polymer is selected from styrene-isoprene-styrene block copolymer and / or styrene-butadiene-styrene block copolymer.

[0007] As a preferred technical solution of the present invention, the styrene polymer is a linear structure, and the styrene polymer does not contain styrene-isoprene diblock polymer (SI).

[0008] As a preferred technical solution of the present invention, the styrene content in the styrene polymer is 25-30wt%.

[0009] As a preferred technical solution of the present invention, the softener is selected from one or more of cyclohexane oil, mineral oil, vegetable oil and fatty acid.

[0010] As a preferred technical solution of the present invention, the softener is cycloalkane oil and mineral oil.

[0011] Preferably, the mineral oil is white mineral oil.

[0012] Further preferably, the kinematic viscosity of the naphthenic oil at 40°C is 150-180 mm 2 / s, the kinematic viscosity of white mineral oil at 40°C is 70-100mm 2 / s.

[0013] As a preferred technical solution of the present invention, in the softener, the weight ratio of cyclohexane oil to mineral oil is (2-6): (1-1.5).

[0014] Preferably, in the softener, the weight ratio of cyclohexane oil to mineral oil is 4.8:1.2.

[0015] The water resistance of glues currently on the market is generally poor, while the glue used for diaper cores requires the glue to have the property of maintaining constant strength when exposed to water. The applicant unexpectedly discovered in the experiment that adding a specific softener compound mixture to the hot melt adhesive system can not only improve the viscosity strength of the hot melt adhesive, but also significantly improve its moisture resistance. The applicant speculates that this may be because the addition of naphthenic oil and mineral oil of specific viscosity can improve the fluidity of the system and affect the dispersibility of the system, thereby improving the molecular pores in the SIS, causing the hot melt adhesive to form a specific cross-linked network, thereby improving the viscosity strength and moisture resistance.

[0016] As a preferred technical solution of the present invention, the tackifier is selected from one or more of hydrogenated petroleum resin, polyisobutylene, and hydrogenated rosin ester.

[0017] Preferably, the tackifier is hydrogenated petroleum resin.

[0018] As a preferred technical solution of the present invention, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include, by weight, 20-45 parts of styrene polymer, 25-45 parts of softener, 25-50 parts of tackifier, 0.05-2 parts of antioxidant and 2-4 parts of fluorescent absorber.

[0019] Preferably, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include, by weight, 23-35 parts of styrene polymer, 28-40 parts of softener, 25-30 parts of tackifier, 0.1-1.8 parts of antioxidant and 2-4 parts of fluorescent absorber.

[0020] The second aspect of the present invention provides a process for preparing a defluorescent pressure-sensitive hot melt adhesive, the preparation process being as follows: (1) preheating and adding materials; (2) stirring; and (3) reacting at 140-145°C.

[0021] Specifically, the preparation process is as follows: (1) preheating and adding materials: preheat the reactor to 115°C, add softener and antioxidant, mix, and add tackifying resin; (2) stirring: stir for 5-20 minutes, add styrene polymer and fluorescent absorber in turn, and stir for 5-20 minutes; (3) 140-145°C reaction: place the reactor under vacuum conditions at 140-145°C to react for 30-45 minutes. After taking out the reactor, filter the solid, cool and dry it to obtain the defluorescent pressure-sensitive hot melt adhesive.

[0022] Preferably, the defluorescent pressure-sensitive hot melt adhesive is applied to composite core diapers.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The introduction of the linear structure SIS which does not contain styrene-isoprene diblock polymer and has a styrene content of 25-30wt% and the synergistic effect of the antioxidant in the system not only improves the softness of the diaper when the hot melt adhesive is used on the diaper, but also makes it have good air permeability, which increases the comfort of the baby when using the diaper; the above SIS can also cooperate with the tackifying resin and the fluorescent absorber, not only does not cause the flocculation of the wood pulp fibers in the non-woven fabric layer, but also unexpectedly improves the uniformity of the wood pulp fibers; a compound mixture of naphthenic oil and white mineral oil is added to the hot melt adhesive system, especially the weight ratio of naphthenic oil to mineral oil is (2-6): (1-1.5), which can not only improve the adhesive strength of the hot melt adhesive, but also significantly improve its moisture resistance; the fluorescent agent in traditional diapers is harmful to the baby's body. The fluorescent absorber added in a specific proportion in the present invention can not only remove the fluorescence of the hot melt adhesive to a certain extent, thereby reducing the fluorescence of the diaper and reducing the odor of the diaper, but also further improve the adhesion of the hot melt adhesive between the layers of the composite core. Even if the humidity is very high, the hot melt adhesive still has a high strength. By controlling the proportion of each substance in the hot melt adhesive, 20-45 parts by weight of styrene polymer, 25-45 parts by weight of softener, 25-50 parts by weight of thickener, 0.05-2 parts by weight of antioxidant and 2-4 parts by weight of fluorescent absorber are compounded, the viscosity and moisture resistance of the hot melt adhesive are improved, and the production process of the hot melt adhesive used in diapers is further simplified. When producing the composite core of diapers, the pressure-sensitive hot melt adhesive, non-woven fabric and SAP can be glued together with the pressure of fingers, which significantly reduces the cost of the diaper core production process and improves production efficiency. DETAILED DESCRIPTION

[0025] Example

[0026] The raw materials for preparing the compositions in the examples are all commercially available, wherein the styrene-isoprene-styrene block copolymer (SIS) used in Examples 1 and 4 is different. The SIS in Example 1 is purchased from Hunan Yuehua, China, with a brand name of YH-1209, and is a linear structure. SIS does not contain styrene-isoprene diblock polymer, and the content of styrene in SIS is 29wt%. The SIS in Example 4 is purchased from Taiwan Rubber, China, with a brand name of 4213N, and is a linear structure. The content of styrene-isoprene diblock polymer (SI) in SIS is 25wt%, and the content of styrene in SIS is 25wt%; naphthenic oil is purchased from Karamay, Xinjiang, China, with a brand name of KN4010, and the kinematic viscosity at 40°C is 160.6mm 2 / s, white mineral oil was purchased from Ssangyong, South Korea, with a brand of 90 and a kinematic viscosity of 89.3 mm at 40 °C 2 / s, hydrogenated petroleum resin was purchased from Shandong Luhua, China, with the brand name LH1100, antioxidant was purchased from BASF, with the brand name antioxidant 1010, and fluorescent absorber was purchased from Dow, with the brand name TS-04.

[0027] Example 1

[0028] This example provides a defluorescent pressure-sensitive hot melt adhesive. The raw materials of the defluorescent pressure-sensitive hot melt adhesive include 26 parts of styrene polymer, 36 parts of softener, 26 parts of tackifier, 0.5 parts of antioxidant and 3 parts of fluorescent absorber by weight.

[0029] The styrenic polymer is a styrene-isoprene-styrene block copolymer (SIS).

[0030] The softener is naphthenic oil and mineral oil, and the mineral oil is white mineral oil.

[0031] The weight ratio of naphthenic oil to mineral oil is 4.8:1.2.

[0032] The tackifier is hydrogenated petroleum resin.

[0033] The preparation method of the defluorescent pressure-sensitive hot melt adhesive is as follows: preheat the reactor to 115°C, add a softener and an antioxidant, mix, add a tackifying resin, stir for 15 minutes, add a styrene polymer and a fluorescent absorber in sequence, stir for 15 minutes, place the reactor under vacuum conditions at 145°C to react for 45 minutes, take out the reactor, filter the solid, cool and dry to obtain the defluorescent pressure-sensitive hot melt adhesive.

[0034] Example 2

[0035] This example provides a defluorescent pressure-sensitive hot melt adhesive. The difference from Example 1 is that, by weight, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include 25 parts of styrene polymer, 30 parts of softener, 25 parts of tackifier, 0.3 parts of antioxidant and 2.4 parts of fluorescent absorber.

[0036] Example 3

[0037] This example provides a defluorescent pressure-sensitive hot melt adhesive. The difference from Example 1 is that, by weight, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include 35 parts of styrene polymer, 40 parts of softener, 28 parts of tackifier, 1 part of antioxidant and 3.5 parts of fluorescent absorber.

[0038] Example 4

[0039] This example provides a defluorescent pressure-sensitive hot melt adhesive, which is different from Example 1 in that, by weight, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include 28 parts of styrene polymer, 34 parts of softener, 27 parts of tackifier, 0.5 parts of antioxidant and 2.8 parts of fluorescent absorber. The source of the styrene polymer is different from that of Example 1.

[0040] Example 5

[0041] This example provides a defluorescent pressure-sensitive hot melt adhesive. The difference from Example 1 is that, by weight, the raw materials of the defluorescent pressure-sensitive hot melt adhesive include 32 parts of styrene polymer, 40 parts of softener, 25-30 parts of tackifier, 1 part of antioxidant and 3.2 parts of fluorescent absorber.

[0042] In the softener, the weight ratio of naphthenic oil to mineral oil is 3:5.

[0043] Performance Testing:

[0044] 1. Peeling strength test: The defluorescent pressure-sensitive hot melt adhesive obtained in Examples 1-5 was mainly used to test the peeling strength between the cast film and the non-woven fabric. A 30 cm × 30 cm PE cast film (purchased from Donica) and a 30 cm × 30 cm hot-pressed non-woven fabric interlayer (purchased from Chuzhou Gusifang Fiber Products Co., Ltd.) were selected. The defluorescent pressure-sensitive hot melt adhesive obtained in Examples 1-5 was respectively coated on the PE cast film, and the coating thickness was controlled at 40-50 μm, and then laminated with a release paper (purchased from Jinshun Paper) to obtain a sample. The above sample and the hot-pressed non-woven fabric interlayer were placed in a constant temperature suite at a temperature of 25°C and a humidity of 70% for 20 minutes, and then the release paper was torn off. The sample was immediately bonded to the non-woven fabric, and then a standard roller (1 kg) was rolled back and forth on the standard cotton cloth once. After standing in a constant temperature suite at a temperature of 25°C and a humidity of 70% for 15 minutes, the cast film and the hot-pressed non-woven fabric interlayer were peeled off at an angle of 180° using an electronic tensile machine. The results are shown in Table 1:

[0045] Table 1

[0046] Example Peel force(N) 1 24.5 2 25.1 3 24.8 4 20.9 5 21.1

[0047] 2. Moisture resistance test: Different from the peeling force test in performance test 1, before the peeling force test in performance test 1, 20 g of the defluorescent pressure-sensitive hot melt adhesive obtained in Example 1-5 was soaked in 500 mL of water for 3 hours, and then the peeling force test was performed. The results are shown in Table 2:

[0048] Table 2

[0049]

[0050]

[0051] 3. Fluorescence test: Different from the peeling force test in performance test 1, before performing the peeling force test in performance test 1, 20 g of the defluorescent pressure-sensitive hot melt adhesive obtained in Example 1 was soaked in 500 mL of water for 3 hours. The immersed pressure-sensitive hot melt adhesive was then irradiated with a fluorescent lamp, and no blue fluorescence was displayed, indicating that the defluorescent pressure-sensitive hot melt adhesive obtained in Example 1 has defluorescent properties.

Claims

1. A defluorescent pressure-sensitive hot melt adhesive. It is characterized in that The raw materials of the defluorescent pressure-sensitive hot melt adhesive include, by weight, 20-45 parts of styrene polymer, 25-45 parts of softener, 25-50 parts of tackifier, 0.05-2 parts of antioxidant and 2-4 parts of fluorescent absorber; The styrene polymer has a linear structure and does not contain a styrene-isoprene diblock polymer; the styrene content of the styrene polymer is 29 wt%; The softener is cyclohexane oil and mineral oil; in the softener, the weight ratio of cyclohexane oil to mineral oil is 4.8:1.

2.

2. The defluorescent pressure-sensitive hot melt adhesive according to claim 1, It is characterized in that The tackifier is selected from one or more of hydrogenated petroleum resin, polyisobutylene, and hydrogenated rosin ester.

3. A process for preparing the defluorescent pressure-sensitive hot melt adhesive according to any one of claims 1 to 2, It is characterized in that The preparation process is as follows: (1) preheating and adding materials; (2) stirring; (3) reacting at 140-145°C.

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