Hot melt pressure sensitive adhesive special for PVC base material and preparation method thereof

Abstract

The application provides a hot melt pressure sensitive adhesive special for PVC substrates, which is prepared by compounding polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butylene)-polystyrene and polystyrene-poly(ethylene-propylene)-polystyrene as elastomer polymers. The prepared hot melt pressure sensitive adhesive has excellent initial adhesion, holding adhesion and peeling strength, and solves the contradictory problems of swelling and gluing efficiency, and can be used for bonding of PVC substrates.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, C09J157 / 02, and particularly to a hot melt pressure-sensitive adhesive for PVC substrates and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) is a linear polymer obtained by free radical polymerization of vinyl chloride monomer under the action of an initiator. It is one of the earliest industrialized plastics, possessing characteristics such as flame retardancy, chemical resistance, excellent electrical insulation, and high mechanical strength. Plasticizing and copolymerization treatments can significantly alter the properties of PVC, enabling it to be manufactured into various pipes, sheets, profiles, films, fibers, coatings, artificial leather, and wire and cable insulation products. Adhesives are commonly used for bonding in the processing and use of these PVC products. However, a common problem in the bonding process of PVC products is adhesive failure. This phenomenon occurs because small-molecule esters are generally used in the production and processing of PVC. These small-molecule esters do not copolymerize with PVC and easily leak into the adhesive structure, causing swelling and damage to the original adhesive structure, resulting in adhesive failure.

[0003] Hot melt pressure-sensitive adhesives have 100% solids content, contain no harmful organic solvents, have simple curing conditions, short curing time, and excellent bonding effect. They can be applied directly to products or through transfer coating. However, the above coating efficiency is relatively slow, especially for smooth PVC products, where hot melt adhesive is not easy to transfer to the surface. Reducing the viscosity of hot melt adhesive can improve coating efficiency, but this operation will aggravate the problem of hot melt adhesive rotting. How to resolve the contradiction between these two issues is an urgent technical problem to be solved.

[0004] Chinese patent CN111071629A discloses a product packaging film and a roll film storage mechanism. The product packaging film includes a heat-insulating and light-shielding layer, a first hot melt adhesive layer, a plastic substrate layer, a second hot melt adhesive layer, a pressure-reducing layer, and a pressure-sensitive adhesive layer stacked sequentially. The plastic substrate layer is made of PVC, TPE, TPU, or TPV. The adhesive includes the following: 1-5 parts of a polyurethane block copolymer composition, 10-15 parts of a styrene-based thermoplastic elastomer, 35-45 parts of a tackifying resin, 25-35 parts of a plasticizer, 5-10 parts of a solid filler, 0.1-0.5 parts of an antioxidant, etc. The adhesive has good heat resistance, low-temperature resistance, and moisture resistance through the reaction of the solid filler with the polyurethane block copolymer composition and the styrene-based thermoplastic elastomer. Chinese patent CN115806776A discloses a pressure-sensitive tape with tensile adhesion loss and its preparation method. The adhesive layers A and B of the tape are made from at least one of SBS and SIS, a tackifying resin, a solvent, colorant, and an antioxidant. The substrate solution of the substrate layer is made from at least one of SEBS and SEPS, fillers, and a solvent. By designing the adhesive and substrate to use structurally similar materials, the adhesive layer adheres well to the substrate layer, exhibiting excellent aging resistance and tensile strength. However, none of these patents address the swelling and adhesive failure phenomena that occur after bonding PVC substrates with adhesives, nor do they resolve the contradiction between swelling and adhesive application efficiency.

[0005] Therefore, it is of great significance to develop an adhesive specifically for bonding PVC products for practical application. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention first provides a special hot-melt pressure-sensitive adhesive for PVC substrates. This hot-melt pressure-sensitive adhesive generates a special and suitable cohesive force, which, while ensuring the initial tack and holding power of the hot-melt pressure-sensitive adhesive, not only prevents the penetration and swelling of small ester molecules in PVC into the cohesive network of the pressure-sensitive adhesive, but also solves the problem of application efficiency within a specific viscosity range.

[0007] Furthermore, based on the total weight of the raw materials, the raw material components of the hot melt pressure-sensitive adhesive include:

[0008] (a) 25-50% ABA-type triblock polymers;

[0009] (b) 15-30% of a mixture of cycloalkanes and / or a mixture of C18-C30 hydrocarbons;

[0010] (c) The remaining amount of tackifying resin.

[0011] Furthermore, in the ABA-type triblock polymer, A is a rigid segment, which is at least one of styrene, polystyrene, polymethylstyrene, and vinyltoluene; B is an elastomer segment, which is selected from at least one of polybutadiene, polyisoprene, polypentadiene, polyisobutylene, polyethylene-butene, polyethylene-propylene, polyethylene, and polybutene.

[0012] Furthermore, the ABA-type triblock polymer includes, but is not limited to, at least one of polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-polyisoprene-polybutadiene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene, polystyrene-poly(ethylene-propylene)-polystyrene, polystyrene-polyethylene-polystyrene, polystyrene-polybutene-polystyrene, and polymethylstyrene-polybutadiene-polymethylstyrene.

[0013] Furthermore, the number-average molecular weight of the ABA-type triblock polymer is ≤200,000, preferably ≤150,000.

[0014] Furthermore, in the ABA-type triblock polymer, the content of the rigid segment, i.e., A, accounts for 10-46 wt% of the total polymer content, and the content of the diblock segment, i.e., AB segment, is 0-65 wt%.

[0015] Preferably, the ABA-type triblock polymer includes polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene, with a mass ratio of 1:(1-4).

[0016] Preferably, a polystyrene-polybutadiene-polystyrene block polymer with a styrene content of 15-40 wt% and a diblock content of 0-40 wt% is selected. At least one of the following can be selected: Maoming Petrochemical F875, Huizhou Lichangrong 3411, 3540, 3546, 3501, Keteng D1155JOP, D1102JSZ, D1101, D1102, D1116, D1133, D1152, D1153, D1155, D1184, D1186, D1189, D1191, DX1192, DX405, and Zhonghe 3406.

[0017] In a preferred embodiment, the polystyrene-polybutadiene-polystyrene contains 28-40 wt% styrene and 12-18 wt% diblock copolymers.

[0018] More preferably, polystyrene-polybutadiene-polystyrene with a Brinell viscosity of 200-2000 cps is selected, and more preferably, polystyrene-polybutadiene-polystyrene with a Brinell viscosity of 580-1500 cps is selected. The Brinell viscosity is the viscosity of a 25% toluene solution at 25°C.

[0019] More preferably, polystyrene-polybutadiene-polystyrene with a melt index of 3-20 g / 10 min is selected, more preferably polystyrene-polybutadiene-polystyrene with a melt index of 8-15 g / 10 min, wherein the melt index is measured at 200°C and 5 kg.

[0020] Furthermore, polystyrene-polyisoprene-polystyrene with a styrene content of 15-40 wt% and a diblock content of 25-65% is selected. Options include at least one of the following: Baling Petrochemical 1124, 1125, 1125H, 1126, 1128, 4019; KETENG 1113PT, 1126PT, D-1124PT, D-1113PT; Formosa Plastics 4114A or 4114N, 4213N, 4255A, 4293A, 4116N; Lee Chang Yung 5516 / D, 5517 / D, 5526; and Ningbo Jinhai Chenguang JH-8161, JH-8162, JH-9163.

[0021] Furthermore, it is preferable to use polystyrene-polyisoprene-polystyrene with an elongation of 800-1500%.

[0022] In a preferred embodiment, the polystyrene-polyisoprene-polystyrene has a styrene content of 15-20 wt% and a diblock content of 35-42 wt%; the elongation is 1000-1200%.

[0023] In a preferred embodiment, the total amount of polystyrene-polybutadiene-polystyrene and polystyrene-polyisoprene-polystyrene accounts for 25-35% of the total weight of the raw materials, and the mass ratio of the two is 1:(1.5-2.5).

[0024] Preferably, the ABA-type triblock polymer further includes polystyrene-poly(ethylene-butene)-polystyrene, accounting for 1-5% of the total raw materials; the polystyrene-poly(ethylene-butene)-polystyrene contains 25-35 wt% styrene and has any one of linear, star-shaped, or mixed structures. Optional materials include at least one of the following: YH-501T, YH-502T, YH-503T, YH-504T, YH-561T, YH-602T, YH-604T from Baling Petrochemical or Yueyang Petrochemical, and at least one of the following from Formosa Plastics Group (Taiwan): 6150, 6151, 6152, 6153, 6154, 6159, 7131, 7126.

[0025] More preferably, the polystyrene-poly(ethylene-butene)-polystyrene accounts for 2-3% of the total raw materials, the styrene content is 30-35 wt%, and the structure is linear.

[0026] Furthermore, the viscosity of the polystyrene-poly(ethylene-butene)-polystyrene is ≥1200 cps; preferably 1500-2500 cps, and the viscosity is the viscosity of a 10% toluene solution at 25°C.

[0027] In a preferred embodiment, the ABA-type triblock polymer further includes polystyrene-poly(ethylene-propylene)-polystyrene, accounting for 1-5% of the total weight of the raw materials; the number average molecular weight of the polystyrene-poly(ethylene-propylene)-polystyrene is less than or equal to 110,000, preferably 50,000-110,000.

[0028] Preferably, the polystyrene-poly(ethylene-propylene)-polystyrene contains 25-40 wt% styrene and has a viscosity of 300-1000 cps; the viscosity test conditions are: 25°C, 15 wt% toluene solution.

[0029] More preferably, the polystyrene-poly(ethylene-propylene)-polystyrene accounts for 2-3% of the total weight of the raw materials, has a number average molecular weight of 50,000-80,000, a viscosity of 300-600 cps, and a styrene content of 28-35 wt%.

[0030] The ABA-type triblock polymers of this application preferably include polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene, and polystyrene-poly(ethylene-propylene)-polystyrene. The cross-linked network structure constructed by the four elastomers provides the basic cohesive force of the hot melt pressure-sensitive adhesive. However, it is necessary to strictly control the content of hard segments and diblocks in each polymer chain to achieve a specific state of cohesive force in the system, avoiding the penetration of small molecules and the swelling and destruction of the cohesive structure. When the content of diblocks is too low or the content of A segments is too high, it will lead to excessively strong cohesive strength of the system, which is not conducive to application efficiency and processing performance. When the content of diblocks is too high or the content of A segments is too low, the structure is unstable and the glue deterioration phenomenon is obvious. When the molecular weight is too high, it will also increase the cross-linking points of the system network structure, resulting in excessively high cohesive strength, which leads to a decrease in application performance and the adhesion of the colloid to the substrate. Only by using four elastomers in combination, taking into account their properties, and further specifying their styrene content, diblock content, molecular weight, melt index, viscosity, and other technical parameters, can the colloid maintain a special cross-linking network and cohesive strength, maintain a balance between initial tack and holding tack, and improve its application efficiency, bonding effect, and bonding stability on PVC substrates.

[0031] Furthermore, the kinematic viscosity at 40°C is 50-200 mmHg for both the cycloalkane-based mixture and the C18-C30 hydrocarbon mixture. 2 / S(GB / T 265).

[0032] Furthermore, the cycloalkane-based mixture contains 35-55 wt% cycloalkane, preferably 40-52 wt%; at least one of the following can be selected: Karamay KN4010, KN4008, KN4012, Ninas Nttex4700, etc.

[0033] Furthermore, in the C18-C30 hydrocarbon mixture, straight-chain alkanes account for 80-95 wt%, and the remainder consists of branched alkanes and cycloalkanes.

[0034] Furthermore, the tackifying resin is selected from at least one of rosin resin, modified rosin resin, terpene resin, petroleum resin, polyacrylate, terpene phenol resin, polycyclopentadiene resin, and hydrogenated polycyclopentadiene resin.

[0035] Furthermore, the modified rosin resin includes, but is not limited to, at least one of pentaerythritol rosin, glycerol rosin, and dehydrated malic acid rosin resin; the softening point of the modified rosin resin is 90-120℃, and the acid value is ≤30; the softening point test adopts the ring and ball method, the same below.

[0036] In a preferred embodiment, the modified rosin resin is pentaerythritol rosin ester and / or rosin glycerol ester, with a softening point of 90-105℃ and an acid value ≤25.

[0037] Further, the petroleum resin is at least one of hydrogenated or non-hydrogenated C5 petroleum resin, hydrogenated or non-hydrogenated C9 petroleum resin, and C5C9 copolymer petroleum resin. Preferably, the petroleum resin is hydrogenated C5 petroleum resin or hydrogenated C9 petroleum resin. The softening point of the hydrogenated C5 petroleum resin or hydrogenated C9 petroleum resin is 95-105℃, and the yellow index is preferably ≤10.

[0038] Preferably, the tackifying resin is modified rosin resin, petroleum resin, and hydrogenated polycyclopentadiene resin, and the amount of modified rosin resin used does not exceed 6% of the total weight of the raw materials; preferably 1-5%.

[0039] Furthermore, the weight ratio of the modified rosin resin, petroleum resin, and hydrogenated polycyclopentadiene resin is (1-5):(15-25):(15-25). All three tackifying resins can be incorporated into the network structure formed by the ABA-type triblock polymer, altering the form and viscoelasticity of the cross-linked network structure. By optimizing the ratio of the three, the adhesive performance, aging resistance, and application efficiency of the hot melt pressure-sensitive adhesive are further improved. Excessive use of modified rosin resin leads to poor aging resistance of the hot melt pressure-sensitive adhesive, while excessive use of hydrogenated polycyclopentadiene resin significantly reduces initial tack.

[0040] Furthermore, the raw materials of this application also include antioxidants accounting for 0.2-1.5% of the total weight of the raw materials, wherein the antioxidants are at least one of phosphite antioxidants, hindered phenolic antioxidants, and dithiopropyl thioester antioxidants.

[0041] In one embodiment, the antioxidant is a hindered phenolic antioxidant.

[0042] Secondly, this application also provides a method for preparing the hot melt pressure-sensitive adhesive, comprising: adding a mixture mainly composed of cycloalkanes and / or a mixture of C18-C30 hydrocarbons to a stirred tank, waiting for the temperature to rise to 120-140°C, adding an ABA-type triblock polymer and stirring until it melts, then adding the remaining raw materials and stirring for 0.5-2 hours before removing the mixture.

[0043] Furthermore, the hot melt pressure-sensitive adhesive described in this application is used for bonding PVC substrates, specifically for bonding PVC substrates to substrates of the same or different materials; the different materials of the substrates include, but are not limited to, at least one of PP substrates, PET substrates, PVC substrates, and PET substrates.

[0044] In a more preferred embodiment, the PVC substrate is an outdoor advertising sticker made of PVC material.

[0045] Beneficial effects

[0046] 1. This application uses polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene and polystyrene-poly(ethylene-propylene)-polystyrene as elastomer polymers by compounding and further strictly limiting their relative content and styrene and diblock content. Under specific technical conditions, it generates special cohesive force to maintain the balance between the initial tack and holding tack of the hot melt pressure-sensitive adhesive. At the same time, it can also avoid the swelling of the hot melt pressure-sensitive adhesive structure by small molecule lipids in the PVC substrate and avoid the phenomenon of adhesive failure.

[0047] 2. This application uses different tackifying resins in combination and strictly controls the content of tackifying resins to further improve the initial tack and holding power of hot melt pressure-sensitive adhesive. By optimizing the softening point, molecular weight and other technical parameters of the tackifying resins, the flow properties of the hot melt pressure-sensitive adhesive are improved, thereby improving its processing performance and coating efficiency on the substrate surface.

[0048] 3. The hot melt pressure-sensitive adhesive prepared in this application has excellent initial tack, holding power and peel strength, and solves the contradiction between swelling and application efficiency, and can be used for bonding PVC substrates. Detailed Implementation

[0049] Example

[0050] Example 1

[0051] This embodiment provides a hot melt pressure-sensitive adhesive for PVC substrates. The raw material composition of the hot melt pressure-sensitive adhesive is as follows: 10% polystyrene-polybutadiene-polystyrene, 20% polystyrene-polyisoprene-polystyrene, 2% polystyrene-poly(ethylene-butene)-polystyrene, 1% polystyrene-poly(ethylene-propylene)-polystyrene, 22% naphthenic oil, 2% modified rosin resin, 20% hydrogenated C5 petroleum resin, 22.8% hydrogenated polycyclopentadiene resin, and 0.2% antioxidant.

[0052] The polystyrene-polybutadiene-polystyrene contains 30wt% styrene, 15wt% diblock copolymer, has a Brookfield viscosity (25℃, 25% toluene solution) of 1200cps, a melt index (200℃, 5kg) of 6g / 10min, and is designated as Keteng D1152; the polystyrene-polyisoprene-polystyrene contains 15wt% styrene, 38% diblock copolymer, and has an elongation of 1100%, and is designated as Li Changrong 5517 / D; the polystyrene-poly(ethylene-butene)-polystyrene contains 33wt% styrene, has a linear structure, and a viscosity (25℃, 10% toluene solution) of 1200cps. The liquid has a viscosity of 2300 cps and is brand name: YH-503T; the polystyrene-poly(ethylene-propylene)-polystyrene has a styrene content of 30 wt%, a viscosity (25℃, 15 wt% toluene solution) of 400 cps, a number average molecular weight of 62,000, and is brand name: Baling Petrochemical 4051; the naphthenic oil is KN4010; the modified rosin resin is rosin pentaerythritol ester (145#) and rosin glycerol ester (138#) in a mass ratio of 1:1; the hydrogenated C5 petroleum resin is H5-1000W; the hydrogenated polycyclopentadiene resin is Exxon E-5400; the antioxidant is antioxidant 1010;

[0053] The preparation method of the hot melt pressure-sensitive adhesive includes: adding naphthenic oil to a stirring vessel, waiting for the temperature to rise to 130°C, adding polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene and polystyrene-poly(ethylene-propylene)-polystyrene and stirring until molten, then adding the remaining raw materials and stirring for 1 hour before taking it out.

[0054] Example 2

[0055] This embodiment provides a hot melt pressure-sensitive adhesive for PVC substrates. The raw material composition of the hot melt pressure-sensitive adhesive is as follows: 15% polystyrene-polybutadiene-polystyrene, 15% polystyrene-polyisoprene-polystyrene, 2% polystyrene-poly(ethylene-butene)-polystyrene, 3% polystyrene-poly(ethylene-propylene)-polystyrene, 25% naphthenic oil, 5% modified rosin resin, 17% hydrogenated C5 petroleum resin, 17% hydrogenated polycyclopentadiene resin, and 1% antioxidant.

[0056] The polystyrene-polybutadiene-polystyrene is designated as Keten D1102; the polystyrene-polyisoprene-polystyrene has a styrene content of 15wt%, a diblock content of 38%, and an elongation of 1330%, and is designated as Jinhai Chenguang JH-9163; the polystyrene-poly(ethylene-butene)-polystyrene is designated as YH-503T; the polystyrene-poly(ethylene-propylene)-polystyrene has a styrene content of 33wt%, a viscosity (25℃, 15wt% toluene solution) of 480cps, and a number-average molecular weight of 105,000, and is designated as Baling Petrochemical 4052; the naphthenic oil is designated as KN4010; the modified rosin resin is designated as pentaerythritol rosin ester; the hydrogenated C5 petroleum resin is designated as H5-1000W; the hydrogenated polycyclopentadiene resin is designated as Exxon E-5400; and the antioxidant is designated as antioxidant 1010.

[0057] The preparation method of the hot melt pressure-sensitive adhesive includes: adding naphthenic oil to a stirring vessel, waiting for the temperature to rise to 140°C, adding polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene and polystyrene-poly(ethylene-propylene)-polystyrene and stirring until molten, then adding the remaining raw materials and stirring for 1 hour before taking it out.

[0058] Example 3

[0059] This embodiment provides a hot melt pressure-sensitive adhesive for PVC substrates. The raw material composition of the hot melt pressure-sensitive adhesive is as follows: 5% polystyrene-polybutadiene-polystyrene, 20% polystyrene-polyisoprene-polystyrene, 3% polystyrene-poly(ethylene-butene)-polystyrene, 2% polystyrene-poly(ethylene-propylene)-polystyrene, 30% naphthenic oil, 4% modified rosin resin, 17.25% hydrogenated C5 petroleum resin, 17.25% hydrogenated polycyclopentadiene resin, and 1.5% antioxidant.

[0060] The modified rosin resin is rosin glycerol ester, and the other raw materials are the same as in Example 1;

[0061] The preparation method of the hot melt pressure-sensitive adhesive includes: adding naphthenic oil to a stirring vessel, waiting for the temperature to rise to 120°C, adding polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene, polystyrene-poly(ethylene-butene)-polystyrene and polystyrene-poly(ethylene-propylene)-polystyrene and stirring until molten, then adding the remaining raw materials and stirring for 2 hours before taking it out.

[0062] Comparative Example 1

[0063] It is basically the same as Example 1, except that the raw material composition of the hot melt pressure-sensitive adhesive is: 20% polystyrene-polybutadiene-polystyrene, 10% polystyrene-polyisoprene-polystyrene, 2% polystyrene-poly(ethylene-butene)-polystyrene, 1% polystyrene-poly(ethylene-propylene)-polystyrene, 22% naphthenic oil, 2% modified rosin resin, 20% hydrogenated C5 petroleum resin, 22.8% hydrogenated polycyclopentadiene resin, and 0.2% antioxidant.

[0064] Comparative Example 2

[0065] It is basically the same as Example 1, except that the raw material composition of the hot melt pressure-sensitive adhesive is: 10% polystyrene-polybutadiene-polystyrene, 20% polystyrene-polyisoprene-polystyrene, 3% polystyrene-poly(ethylene-butene)-polystyrene, 22% naphthenic oil, 2% modified rosin resin, 20% hydrogenated C5 petroleum resin, 22.8% hydrogenated polycyclopentadiene resin, and 0.2% antioxidant.

[0066] Comparative Example 3

[0067] It is basically the same as Example 1, except that: the polystyrene-polybutadiene-polystyrene contains 31wt% styrene, 78wt% diblock, has a Brookfield viscosity (25℃, 25% toluene solution) of 630cps, a melt index (200℃, 5kg) of 10g / 10min, and is graded KETEN D-1118ET.

[0068] Comparative Example 4

[0069] It is basically the same as Example 1, except that the raw material composition of the hot melt pressure-sensitive adhesive is: 10% polystyrene-polybutadiene-polystyrene, 20% polystyrene-polyisoprene-polystyrene, 2% polystyrene-poly(ethylene-butene)-polystyrene, 1% polystyrene-poly(ethylene-propylene)-polystyrene, 22% naphthenic oil, 8% modified rosin resin, 17% hydrogenated C5 petroleum resin, 19.8% hydrogenated polycyclopentadiene resin, and 0.2% antioxidant.

[0070] Comparative Example 5

[0071] It is basically the same as Example 1, except that the polystyrene-poly(ethylene-propylene)-polystyrene contains 30 wt% styrene, has a number average molecular weight of 165,000, and is graded Baling Petrochemical 4053.

[0072] Comparative Example 6

[0073] It is basically the same as Example 1, except that the naphthenic oil is replaced with paraffin oil, grade 150#.

[0074] Performance testing methods:

[0075] 1. Initial tack and holding power: According to standard GB / T31125—2014, the amount of adhesive applied is 40g;

[0076] 2. Peel strength: Tested according to standard GB / T 2792-2014;

[0077] 3. Adhesive Deterioration Test: The hot melt pressure-sensitive adhesive of the example is applied to the PVC advertising sticker and bonded. It is placed at 50°C for 7 days to determine whether there is adhesive deterioration. If there is no deterioration, it is considered to pass; otherwise, it is considered to fail.

[0078] Performance test results:

[0079] The test results are shown in Table 1.

[0080] Table 1

[0081]

Claims

1. A hot melt pressure-sensitive adhesive for PVC substrates, characterized in that, The raw material components of the hot melt pressure-sensitive adhesive, based on the total weight of the raw materials, include: (a)25 50% of A B Type A triblock polymers; (b)15 30% of a mixture primarily composed of cycloalkanes and / or C18 hydrocarbons A mixture of hydrocarbons with C30 content; (c) The remaining amount of tackifying resin; The A B Type A triblock polymers include polystyrene. Polybutadiene Polystyrene and polystyrene Polyisoprene Polystyrene, the mass ratio of the two is 1:(1 4); A styrene content of 15% was selected. 40wt%, diblock content is 0 40wt% polystyrene polybutadiene Polystyrene block polymer; selected with a styrene content of 15-40 wt% and a diblock content of 25%. 65% polystyrene Polyisoprene Polystyrene; Select a melt flow index of 3 20g / 10min polystyrene Polybutadiene Polystyrene; using an elongation of 800 1500% polystyrene Polyisoprene Polystyrene; The raw materials also include polystyrene. Poly(ethylene butene) Polystyrene, accounting for 1% of the total raw materials 5%, styrene content is 25%. 35wt%, viscosity 1500-2500cps; The raw materials also include polystyrene. Poly(ethylene) Acrylic) Polystyrene, accounting for 1% of the total weight of raw materials 5%; number-average molecular weight is 5 110,000; The tackifying resin is a modified rosin resin, petroleum resin, and hydrogenated polycyclopentadiene resin, and the amount of the modified rosin resin used does not exceed 6% of the total weight of the raw materials; The weight ratio of the modified rosin resin, petroleum resin, and hydrogenated polycyclopentadiene resin is (1:1). 5): (15 25): (15 25); The petroleum resin is at least one of hydrogenated or non-hydrogenated C5 petroleum resin, hydrogenated or non-hydrogenated C9 petroleum resin, and C5C9 copolymer petroleum resin.

2. The method for preparing the hot melt pressure-sensitive adhesive according to claim 1, characterized in that, include: Add a mixture primarily composed of cycloalkanes and / or C18 hydrocarbons to a stirred tank. A C30 hydrocarbon mixture, when the temperature rises to 120... 140℃, add A B The type A triblock polymer was stirred until it reached a molten state, then the remaining raw materials were added and stirred for 0.5 minutes. Remove after 2 hours.

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