Hot-melt pressure-sensitive adhesive as well as preparation method and application thereof

Abstract

The invention provides a hot-melt pressure-sensitive adhesive as well as a preparation method and application thereof, and belongs to the technical field of hot-melt pressure-sensitive adhesives. The invention provides a hot-melt pressure-sensitive adhesive. The hot-melt pressure-sensitive adhesive is prepared from the following raw materials in parts by mass: 30-45 parts of a thermoplastic elastomer, 35-55 parts of tackifying resin, 10-30 parts of a plasticizer, 1-5 parts of a low-temperature additive and 0.3-1.2 parts of an antioxidant, the Tg of the low-temperature auxiliary agent is-80 to-95 DEG C. By adopting the thermoplastic elastomer with higher content, the filling proportion of the plasticizer can be increased, so that small molecular oil is not easy to separate out, and the oil leakage is reduced; the overall Tg value of the hot-melt pressure-sensitive adhesive can be reduced by the high-content thermoplastic elastomer, so that the low-temperature performance is improved; and the low-temperature auxiliary agent has a plasticizing property, has a low Tg value, and can greatly reduce the Tg value of the hot-melt pressure-sensitive adhesive, so that the low-temperature performance of the hot-melt pressure-sensitive adhesive is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot melt pressure sensitive adhesives, and in particular relates to a hot melt pressure sensitive adhesive and a preparation method and application thereof. Background Art

[0002] At present, hot melt pressure sensitive adhesive has the characteristics of high solid content and low VOC, and is widely used in the fields of labeling, packaging, medical and health care, and self-adhesive stickers. Its low cost, environmental friendliness, and good low temperature performance can effectively replace traditional solvent-based pressure sensitive adhesives and some emulsion-based pressure sensitive adhesives. As the field of cold chain logistics becomes more and more perfect, the demand for low-temperature labels is increasing, and the requirements for the adhesive performance and die-cutting performance of hot melt pressure sensitive adhesives are also increasing.

[0003] In order to ensure good low-temperature performance, the commercially available hot-melt pressure-sensitive adhesive for low-temperature labels needs to add a large amount of plasticizer in the formula, but it will cause oil seepage. Therefore, how to improve the hot-melt pressure-sensitive adhesive so that it has both excellent low-temperature performance and anti-oil seepage performance has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a hot melt pressure sensitive adhesive and a preparation method and application thereof. The hot melt pressure sensitive adhesive provided by the present invention not only has excellent low temperature performance, but also has excellent anti-oil permeation performance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a hot melt pressure-sensitive adhesive, which is prepared from the following raw materials in parts by weight:

[0007] 30-45 parts of thermoplastic elastomer, 35-55 parts of tackifying resin, 10-30 parts of plasticizer, 1-5 parts of low temperature auxiliary agent and 0.3-1.2 parts of antioxidant;

[0008] The Tg of the low-temperature auxiliary agent is -80 to -95°C.

[0009] Preferably, the hot melt pressure-sensitive adhesive is prepared from the following raw materials in parts by weight:

[0010] 37-44 parts of thermoplastic elastomer, 38-50 parts of tackifying resin, 15-25 parts of plasticizer, 3-5 parts of low temperature auxiliary agent and 0.5-1.0 part of antioxidant.

[0011] Preferably, the thermoplastic elastomer includes at least one of SIS, SBS and SSBR.

[0012] Preferably, the melt flow index of the SIS is 8 to 35 g / 10 min.

[0013] Preferably, the diblock content of the SIS is 15-90%, and the block ratio of SIS is (15-25):(85-75).

[0014] Preferably, the tackifying resin comprises at least one of terpene resin, petroleum resin, rosin glycerol ester, rosin pentaerythritol ester and rosin modified resin.

[0015] Preferably, the plasticizer includes at least one of naphthenic oil, PE wax, polyisoprene and polyisobutylene.

[0016] Preferably, the low temperature auxiliary agent is aliphatic hydrocarbon synthetic oil.

[0017] The present invention also provides a method for preparing the hot melt pressure sensitive adhesive described in the above technical solution, comprising:

[0018] Thermoplastic elastomer, tackifying resin, plasticizer, low temperature auxiliary agent and antioxidant are mixed to obtain hot melt pressure sensitive adhesive.

[0019] The present invention also provides the use of the hot melt pressure sensitive adhesive described in the above technical solution or the hot melt pressure sensitive adhesive prepared by the preparation method described in the above technical solution in a low temperature self-adhesive label.

[0020] The present invention provides a hot melt pressure-sensitive adhesive, which is prepared from the following raw materials by mass: 30 to 45 parts of thermoplastic elastomer, 35 to 55 parts of tackifying resin, 10 to 30 parts of plasticizer, 1 to 5 parts of low-temperature auxiliary agent and 0.3 to 1.2 parts of antioxidant; the Tg of the low-temperature auxiliary agent is -80 to -95°C. The present invention can increase the filling ratio of the plasticizer by adopting a higher content of thermoplastic elastomer, so that small molecule oil is not easy to precipitate and oil seepage is reduced; a higher content of thermoplastic elastomer can reduce the overall Tg value of the hot melt pressure-sensitive adhesive, thereby improving the low-temperature performance; the low-temperature auxiliary agent plays a plasticizing role, and its Tg value is relatively low, which can greatly reduce the Tg value of the hot melt pressure-sensitive adhesive, thereby improving the low-temperature performance. Experimental results show that the annular initial adhesion of the hot melt pressure-sensitive adhesive provided by the present invention is 13 to 17N, the annular initial adhesion of -0°C is 13 to 18N, the annular initial adhesion of -15°C is 1 to 7N, and the oil seepage resistance is 3 to 4d. DETAILED DESCRIPTION

[0021] The present invention provides a hot melt pressure-sensitive adhesive, which is prepared from the following raw materials in parts by weight:

[0022] 30-45 parts of thermoplastic elastomer, 35-55 parts of tackifying resin, 10-30 parts of plasticizer, 1-5 parts of low temperature auxiliary agent and 0.3-1.2 parts of antioxidant;

[0023] The Tg of the low-temperature auxiliary agent is -80 to -95°C.

[0024] The present invention has no particular limitation on the sources of the raw materials, and commercially available products known to those skilled in the art may be used.

[0025] In terms of mass fraction, the raw materials for preparing the hot melt pressure sensitive adhesive of the present invention include 30 to 45 parts of thermoplastic elastomer, preferably 37 to 44 parts, and more preferably 37 to 40 parts. The present invention can increase the filling ratio of the plasticizer by using a higher content of thermoplastic elastomer, so that small molecule oil is not easy to precipitate and oil seepage is reduced; a higher content of thermoplastic elastomer can reduce the Tg value of the hot melt pressure sensitive adhesive as a whole, thereby improving the low temperature performance.

[0026] In the present invention, the thermoplastic elastomer preferably includes at least one of SIS, SBS and SSBR, more preferably SIS and SSBR.

[0027] In the present invention, the molecular structure of the thermoplastic elastomer is preferably star-shaped and / or linear. The star-shaped structure rubber used in the present invention has high diblock content and high styrene content due to its structural morphology, which improves wettability while ensuring high cohesive strength.

[0028] In the present invention, the melt flow index of the SIS is preferably 8-35 g / 10 min, more preferably 12-30 g / 10 min; the diblock content of the SIS is preferably 15-90%, more preferably 60-90%; the block ratio of the SIS is preferably (15-25): (85-75), more preferably (20-25): (80-75); the styrene content of the SIS is preferably 15-16%. The present invention controls the parameters of the SIS within the above range to further improve the low temperature performance and oil permeation resistance of the hot melt pressure sensitive adhesive.

[0029] In the present invention, the number average molecular weight of the SIS is preferably 110,000 to 160,000, more preferably 120,000 to 150,000.

[0030] In the present invention, when the thermoplastic elastomer is SIS, the mass ratio of the linear structure SIS with a melt flow index of 12 g / 10 min, a diblock content of 60% and a styrene content of 15% to the linear structure SIS with a melt flow index of 30 g / 10 min, a diblock content of 90% and a styrene content of 16% is preferably 1:1.5. The present invention adopts two SISs with different parameters and limits their ratio within the above range, which can improve processing performance, facilitate die cutting, and improve fluidity.

[0031] In the present invention, when the thermoplastic elastomer is SIS and SSBR, the mass ratio of SIS to SSBR is preferably 1:(0.01-0.2), more preferably 1:(0.15-0.16). The introduction of SSBR in the present invention can improve low-temperature fluidity and low-temperature viscosity, but affects oil permeation resistance, so by limiting the ratio of SSBR to SIS within the above range, the hot melt pressure-sensitive adhesive can have both excellent low-temperature performance and oil permeation resistance.

[0032] In the present invention, the styrene content of the SSBR is preferably 24-26%, more preferably 25%; the block styrene content of the SSBR is preferably 15-20%, more preferably 17.5%. The present invention limits the parameters of the SSBR to the above ranges to improve the viscosity of the hot melt pressure sensitive adhesive.

[0033] The present invention has no particular limitation on the molecular weight of the SSBR, and commercially available products known to those skilled in the art may be used.

[0034] Based on 30-45 parts by mass of thermoplastic elastomer, the raw materials for preparing the hot melt pressure sensitive adhesive of the present invention also include 35-55 parts of tackifying resin, preferably 38-50 parts, more preferably 46-48 parts. The tackifying resin used in the present invention can improve the viscosity of the hot melt pressure sensitive adhesive.

[0035] In the present invention, the tackifying resin preferably includes at least one of terpene resin, petroleum resin, rosin glycerol ester, rosin pentaerythritol ester and rosin modified resin, more preferably C5 petroleum resin, styrene-modified C5 petroleum resin and phenolic-modified rosin resin.

[0036] In the present invention, the mass ratio of the C5 petroleum resin, the styrene-modified C5 petroleum resin and the phenolic-modified rosin resin is preferably 1:1:0.3. The present invention uses a variety of tackifying resins to increase polar groups, thereby increasing adhesion and reducing costs.

[0037] In the present invention, the softening point of the terpene resin is preferably 95-100°C, more preferably 96-98°C; the petroleum resin is preferably C5 petroleum resin, styrene-modified C5 petroleum resin, C5 / C9 copolymerized petroleum resin or liquid C5 resin; the softening point of the C5 petroleum resin is preferably 90-110°C, more preferably 100°C; the softening point of the styrene-modified C5 petroleum resin is preferably 90-100°C, more preferably 95°C; the softening point of the C5 / C9 copolymerized petroleum resin is preferably 90~94℃, more preferably 91~93℃; the softening point of the liquid C5 resin is preferably 5~15℃, more preferably 10℃; the softening point of the rosin glycerol ester is preferably 90~100℃, more preferably 90~95℃; the softening point of the rosin pentaerythritol ester is preferably 100~105℃, more preferably 102~104℃; the rosin modified resin is preferably phenolic modified rosin resin; the softening point of the rosin modified resin is preferably 90~110℃, more preferably 90~105℃. In the present invention, controlling the softening point of the tackifying resin within the above range can further improve the viscosity of the hot melt pressure-sensitive adhesive.

[0038] The present invention has no particular limitation on the molecular weight of the terpene resin, and commercially available products known to those skilled in the art may be used.

[0039] Based on 30-45 parts by mass of thermoplastic elastomer, the raw materials for preparing the hot melt pressure sensitive adhesive of the present invention also include 10-30 parts of plasticizer, preferably 15-25 parts, more preferably 19-23 parts. The plasticizer used in the present invention can improve the fluidity of the hot melt pressure sensitive adhesive.

[0040] In the present invention, the plasticizer preferably includes at least one of naphthenic oil, PE wax, polyisoprene and polyisobutylene, and more preferably naphthenic oil.

[0041] In the present invention, the Cn value of the naphthenic oil is preferably ≥40%; the naphthenic oil is preferably KN4010.

[0042] In the present invention, the viscosity of the PE wax at 140° C. is preferably ≤4000 mPa·s, more preferably 375 mPa·s.

[0043] In the present invention, the number average molecular weight of the polyisoprene is preferably ≤1000.

[0044] In the present invention, the number average molecular weight of the polyisobutylene is preferably 950.

[0045] The present invention can further improve the plasticizing effect by limiting the parameters of the plasticizer, thereby further improving the fluidity.

[0046] Based on 30 to 45 parts by mass of the thermoplastic elastomer, the raw materials for preparing the hot melt pressure-sensitive adhesive of the present invention further include 1 to 5 parts of a low temperature additive, preferably 3 to 5 parts; the low temperature additive is preferably aliphatic hydrocarbon synthetic oil; the Tg of the low temperature additive is -80 to -95°C, more preferably -90°C. The low temperature additive used in the present invention has a plasticizing property, and its Tg value is relatively low, which can significantly reduce the Tg value of the hot melt pressure-sensitive adhesive, thereby improving the low temperature performance.

[0047] Based on the mass fraction of thermoplastic elastomer being 30 to 45 parts, the raw materials for preparing the hot melt pressure-sensitive adhesive of the present invention further include 0.3 to 1.2 parts of antioxidant, preferably 0.5 to 1.0 parts; the antioxidant is preferably a mixture of pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and tris(2,4-di-tert-butylphenyl)phosphite; the mass ratio of pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) to tris(2,4-di-tert-butylphenyl)phosphite is preferably (1 to 2): 1. The present invention adopts a combination of the above two antioxidants, which can capture free radicals generated in different high temperature zones and prevent the hot melt pressure-sensitive adhesive from thermal oxidation aging to the greatest extent.

[0048] The present invention can increase the filling ratio of the plasticizer by adopting a higher content of thermoplastic elastomer, thereby making it difficult for small molecule oil to precipitate and reducing oil seepage; the higher content of thermoplastic elastomer can reduce the overall Tg value of the hot melt pressure-sensitive adhesive, thereby improving the low-temperature performance; the low-temperature auxiliary agent plays a plasticizing role, and its Tg value is relatively low, which can significantly reduce the Tg value of the hot melt pressure-sensitive adhesive, thereby improving the low-temperature performance.

[0049] The invention improves the low-temperature fluidity of the hot-melt pressure-sensitive adhesive by increasing the proportion of high-diblock-content thermoplastic elastomer and introducing a low-temperature additive, and at the same time has a good pasting effect at room temperature and maintains good cohesive strength, so that the hot-melt pressure-sensitive adhesive has both room-temperature viscosity and excellent low-temperature performance; the hot-melt pressure-sensitive adhesive of the invention has the advantages of good initial adhesion, high peel strength and good sustained adhesion, and has excellent die-cutting performance, and can be used for low-temperature self-adhesive labels.

[0050] The hot melt pressure-sensitive adhesive of the present invention has high viscosity at room temperature and maintains good low-temperature wettability. The viscosity of the labeling hot melt pressure-sensitive adhesive at -20°C at 170°C is relatively low, which can improve the leveling property of the hot melt pressure-sensitive adhesive during high-temperature coating, thereby increasing the coating speed and reducing production energy consumption. The present invention selects suitable materials and proportions, and the hot melt pressure-sensitive adhesive has moderate hardness and softness. While maintaining high viscosity at room temperature and low temperature, it does not produce oil seepage and glue overflow. During the die-cutting process, high-speed die-cutting can be performed, reducing downtime and reducing material waste.

[0051] The present invention also provides a method for preparing the hot melt pressure sensitive adhesive described in the above technical solution, comprising:

[0052] Thermoplastic elastomer, tackifying resin, plasticizer, low temperature auxiliary agent and antioxidant are mixed to obtain hot melt pressure sensitive adhesive.

[0053] In the present invention, the mixing of the thermoplastic elastomer, tackifying resin, plasticizer, low-temperature aid and antioxidant preferably comprises the following steps:

[0054] (1) mixing a plasticizer and a low-temperature auxiliary agent to obtain a first mixed material;

[0055] (2) mixing the first mixed material obtained in step (1) with an antioxidant to obtain a second mixed material;

[0056] (3) mixing the second mixed material obtained in step (2) with a thermoplastic elastomer to obtain a third mixed material;

[0057] (4) Mixing the third mixed material obtained in step (3) with a tackifying resin.

[0058] In the present invention, the plasticizer is preferably mixed with the low-temperature auxiliary agent to obtain a first mixed material.

[0059] The present invention has no special limitation on the operation of mixing the plasticizer and the low-temperature auxiliary agent, and the technical scheme for preparing the mixed material well known to those skilled in the art can be adopted.

[0060] After obtaining the first mixed material, the present invention preferably mixes the first mixed material with an antioxidant to obtain a second mixed material.

[0061] In the present invention, the mixing of the first mixed material and the antioxidant is preferably carried out under stirring conditions; the stirring temperature is preferably 120-130°C. The present invention has no particular limitation on the stirring time, as long as there are no antioxidant particles. The mixing at 120-130°C can accelerate the dissolution rate of the antioxidant and prevent the plasticizer and the low-temperature auxiliary agent from being thermally aged due to overheating.

[0062] After obtaining the second mixed material, the present invention preferably mixes the second mixed material with a thermoplastic elastomer to obtain a third mixed material.

[0063] In the present invention, the thermoplastic elastomer is preferably added slowly. The present invention has no special limitation on the operation of slow addition, and the operation well known to those skilled in the art can be adopted. The slow addition of the present invention can avoid agglomeration caused by adding all at once.

[0064] In the present invention, the mixing of the second mixed material and the thermoplastic elastomer is preferably carried out under stirring conditions; the stirring temperature is preferably 145 to 155° C.; and the stirring time is preferably 1.5 to 2 hours. The present invention has no particular limitation on the stirring rate, and the raw materials can be mixed completely. In the present invention, mixing at 145 to 155° C. can melt the thermoplastic elastomer into a uniform mixture.

[0065] In the present invention, the mixing of the second mixed material and the thermoplastic elastomer is preferably carried out under vacuum conditions; the vacuum degree of the vacuum is preferably -0.085 to -0.01 MPa. The vacuum of the present invention can prevent rubber, resin, naphthenic oil, etc. from thermal oxidation aging under oxygen and high temperature.

[0066] After obtaining the third mixed material, the present invention preferably mixes the third mixed material with a tackifying resin.

[0067] In the present invention, the tackifying resin is preferably added slowly; the mixing of the third mixed material and the tackifying resin is preferably carried out under stirring; the stirring preferably includes sequentially performing high-speed stirring and low-speed stirring. In the present invention, the tackifying resin is added slowly to prevent the tackifying resin with a lower temperature from being added to the molten thermoplastic elastomer to cause agglomeration.

[0068] In the present invention, the temperature of the high-speed stirring is preferably 145-155°C, more preferably 150°C; the time of the high-speed stirring is preferably 0.5-1.5h, more preferably 0.5-1h; according to the condition of the equipment motor and the stirring paddle, the speed of the high-speed stirring is preferably 30-35rpm. The high-speed stirring of the present invention can make the raw materials mixed more uniformly.

[0069] In the present invention, the rotation speed of the low-speed stirring is preferably 0.5-1 rpm, more preferably 1 rpm. The present invention cools at a low speed to prevent the molecular chains of the hot-melt pressure-sensitive adhesive from being destroyed under high-speed shearing, resulting in a decrease in cohesion.

[0070] The present invention has no particular limitation on the temperature of the low-speed stirring, and the stirring can be carried out under natural cooling.

[0071] In the present invention, the mixing of the third mixed material and the tackifying resin is preferably carried out under vacuum conditions; the vacuum degree of the vacuum is preferably -0.085 to -0.01 MPa.

[0072] After the thermoplastic elastomer, tackifying resin, plasticizer, low-temperature additive and antioxidant are mixed, the present invention preferably performs glue extraction on the mixed product to obtain a hot melt pressure-sensitive adhesive.

[0073] The present invention has no special limitation on the glue dispensing operation, and it can be performed at a temperature above 140° C. When the hot melt pressure sensitive adhesive is dispensed at a temperature above 140° C., the hot melt pressure sensitive adhesive has good fluidity, and the glue dispensing efficiency can be improved.

[0074] In the present invention, when the thermoplastic elastomer is SSBR, it is preferably crushed before use. Crushing the SSBR in the present invention is conducive to oil absorption and melting, and has better uniformity.

[0075] The present invention has no particular limitation on the pulverizing operation, and any operation well known to those skilled in the art may be used.

[0076] The preparation method provided by the invention is simple and easy to industrialize.

[0077] The present invention also provides the use of the hot melt pressure sensitive adhesive described in the above technical solution or the hot melt pressure sensitive adhesive prepared by the preparation method described in the above technical solution in a low temperature self-adhesive label.

[0078] The present invention has no special limitation on the operation of applying the hot melt pressure sensitive adhesive in the low temperature self-adhesive label, and the operation well known to those skilled in the art can be adopted.

[0079] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] Example 1

[0081] The hot melt pressure sensitive adhesive is prepared from the following raw materials in parts by weight: 37 parts of thermoplastic elastomer, 38 parts of tackifying resin, 19 parts of plasticizer, 5 parts of low temperature auxiliary agent and 1 part of antioxidant;

[0082] The thermoplastic elastomer is composed of thermoplastic elastomer 1 and thermoplastic elastomer 2, and the mass ratio of thermoplastic elastomer 1 to thermoplastic elastomer 2 is 12:25;

[0083] Thermoplastic elastomer 1 is a linear structure SIS, with a melt flow index of 12 g / 10 min, a diblock content of 60%, and a styrene content of 15%, produced by Xingzhi;

[0084] Thermoplastic elastomer 2 is a linear structure SIS, with a melt flow index of 30 g / 10 min, a diblock content of 90%, and a styrene content of 16%, produced by Xingzhi;

[0085] The tackifying resin is composed of C5 petroleum resin, styrene-modified C5 petroleum resin and phenolic modified rosin resin, and the mass ratio of C5 petroleum resin, styrene-modified C5 petroleum resin and phenolic modified rosin resin is 17:16:5;

[0086] C5 petroleum resin is JH-3200 from Jinhai, with a softening point of 100°C;

[0087] The styrene-modified C5 petroleum resin is JH-3204 from Jinhai, with a softening point of 95°C;

[0088] Phenolic resin modified rosin resin is produced by Xingzhi, with a softening point of 90℃;

[0089] The plasticizer is naphthenic oil KN-4010;

[0090] The low-temperature additive is aliphatic hydrocarbon synthetic oil with a Tg point of -90°C, produced by Shanghai Xisen;

[0091] The antioxidant is a mixture of pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and tris(2,4-di-tert-butylphenyl)phosphite, with a mass ratio of 2:1;

[0092] The preparation method of the hot melt pressure sensitive adhesive is:

[0093] The plasticizer and low-temperature additive were put into the reactor, stirred and heated, and the antioxidant was added at 130°C. After stirring for 10 minutes until there were no obvious antioxidant particles in the reactor, the thermoplastic elastomer was slowly added, the temperature in the reactor was increased to 145°C, and the vacuum was evacuated to a vacuum degree of -0.085MPa. The thermoplastic elastomer was stirred at a speed of 30rpm for 2h until the thermoplastic elastomer melted into a uniform mixture; then C5 petroleum resin and styrene-modified C5 resin were added to the reactor, the temperature in the reactor was controlled to 150°C, and the vacuum was evacuated to -0.085MPa. At the same time, the stirring rate was increased to 35rpm, and the mixture was stirred for 0.5h. N 2 Set the vacuum degree to 0, open the lid and slowly add phenolic modified rosin resin, evacuate to -0.085MPa, stir for 1h until the hot melt pressure sensitive adhesive becomes a uniform transparent mixture, then reduce the stirring to 1rpm, turn off the heating at the same time, and discharge the glue to obtain the hot melt pressure sensitive adhesive.

[0094] Example 2

[0095] On the basis of Example 1, the C5 petroleum resin was replaced by a terpene resin, the softening point of the terpene resin was 95° C., and it was SYLVARES 6100 produced by Karton, and other conditions remained unchanged.

[0096] Example 3

[0097] On the basis of Example 1, the styrene-modified C5 petroleum resin was replaced by rosin glycerol ester, the softening point of rosin glycerol ester was 90° C., and it was 384T produced by Komolin, and other conditions remained unchanged.

[0098] Example 4

[0099] On the basis of Example 1, 5 parts of cyclohexane oil KN-4010 were replaced by PE wax, the viscosity of PE wax at 140° C. was 375 mPa·s, and other conditions remained unchanged.

[0100] Example 5

[0101] The type of thermoplastic elastomer is changed on the basis of Example 1, the thermoplastic elastomer is composed of thermoplastic elastomer 1, thermoplastic elastomer 2 and thermoplastic elastomer 3, and the mass ratio of thermoplastic elastomer 1, thermoplastic elastomer 2 and thermoplastic elastomer 3 is 12:20:5;

[0102] Thermoplastic elastomer 3 is a linear SSBR, a random block butadiene styrene copolymer, with a styrene content of 25% and a block styrene content of 17.5%, and is Solprene 1205 from Dynasol;

[0103] Thermoplastic elastomer 3 was crushed before use, and other conditions remained unchanged.

[0104] Comparative Example 1

[0105] The hot melt pressure sensitive adhesive is prepared from the following raw materials in parts by weight: 32 parts of thermoplastic elastomer, 50 parts of tackifying resin, 18 parts of plasticizer and 1 part of antioxidant;

[0106] The thermoplastic elastomer is composed of thermoplastic elastomer A, thermoplastic elastomer B and thermoplastic elastomer C, and the mass ratio of thermoplastic elastomer A, thermoplastic elastomer B and thermoplastic elastomer C is 10:12:10;

[0107] Thermoplastic elastomer A is a star-shaped SIS with a melt flow index of 23 g / 10 min, a diblock content of 75%, a styrene content of 18%, and is Shandong Jusheng 4270;

[0108] Thermoplastic elastomer B is a linear structure SIS, with a melt flow index of 10 g / 10 min, a diblock content of 50%, a styrene content of 16%, and is Jinhai JH-8161;

[0109] Thermoplastic elastomer C is a linear structure SIS, with a melt flow index of 10 g / 10 min, a diblock content of 0%, a styrene content of 15%, and is Jinhai JH-8151;

[0110] The tackifying resin is composed of C5 petroleum resin, styrene-modified C5 petroleum resin and phenolic modified rosin resin, and the mass ratio of C5 petroleum resin, styrene-modified C5 petroleum resin and phenolic modified rosin resin is 25:10:15; other conditions are the same as those in Example 1.

[0111] Comparative Example 2

[0112] On the basis of Example 1, the low-temperature auxiliary agent was omitted, the content of the plasticizer was set to 24 parts, and other conditions remained unchanged.

[0113] The hot melt pressure-sensitive adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were tested for loop initial adhesion, loop initial adhesion at 0°C, loop initial adhesion at -15°C, and oil permeation resistance. The results are shown in Table 1; wherein the test method for loop initial adhesion is: refer to the FINAT technical manual FTM9 test method, expressed in Newton (N); the test method for low-temperature loop initial adhesion is: test under low temperature environment, the test method refers to the FINAT technical manual FTM9 test method, expressed in Newton (N); the test method for oil permeation resistance is: apply the hot melt pressure-sensitive adhesive on 80g / m 2 The back of the coated paper is laminated with release paper, a 1kg weight is placed on the surface of the paper, and the paper is placed in an environment of 65±1℃, 85±5%RH. The time it takes for oil spots to appear on the paper surface is observed, expressed in days (d).

[0114] Table 1 Performance data of hot melt pressure sensitive adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 2

[0115] Experimental groups Ring initial adhesion (N) -0℃ Ring initial adhesion (N) -15℃ Ring initial adhesion(N) Anti-oil seepage effect (d) Example 1 15.3 17.5 4.5 4 Example 2 16.4 15.2 3.1 4 Example 3 15.2 17.2 3.2 3 Example 4 14.2 12.8 1.2 4 Example 5 15.2 14.2 4.0 3 Comparative Example 1 25.4 4.3 ＜1 6 Comparative Example 2 16.3 12.6 ＜1 2

[0116] As can be seen from Table 1, by comparing Example 1 with Comparative Example 2, it can be seen that after the low-temperature auxiliary agent is replaced by cyclohexane oil, the low-temperature viscosity of the hot melt pressure-sensitive adhesive is reduced; the amount of cyclohexane oil added in Comparative Example 2 is too high, resulting in serious oil seepage; by comparing Example 1 and Example 4, it can be seen that after 5 parts of PE wax are replaced with cyclohexane oil, the modulus of the hot melt pressure-sensitive adhesive is increased, the fluidity of the hot melt pressure-sensitive adhesive is reduced, and the viscosity is slightly decreased; by comparing Example 1 and Example 5, it can be seen that after adding SSBR thermoplastic elastomer, the strength of the overall hot melt pressure-sensitive adhesive decreases, resulting in a slightly lower viscosity test value, but maintains good fluidity at low temperatures, the oil control ability of the rubber is insufficient, and therefore the oil resistance ability is reduced to a certain extent; by comparing Example 1 and Comparative Example 1, it can be seen that reducing the rubber ratio, increasing the resin ratio, and reducing the plasticizer ratio can improve the room temperature viscosity, but the low temperature viscosity decreases, and the oil resistance ability is greatly improved.

[0117] It can be seen from the above embodiments and comparative examples that the hot melt pressure sensitive adhesive provided by the present invention not only has excellent low temperature performance, but also has excellent anti-oil permeation performance.

[0118] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hot melt pressure-sensitive adhesive is prepared from the following raw materials in parts by weight: 30-45 parts of thermoplastic elastomer, 35-55 parts of tackifying resin, 10-30 parts of plasticizer, 1-5 parts of low temperature auxiliary agent and 0.3-1.2 parts of antioxidant; The Tg of the low-temperature auxiliary agent is -80 to -95°C.

2. The hot melt pressure sensitive adhesive according to claim 1, characterized in that Prepared from the following raw materials in parts by weight: 37-44 parts of thermoplastic elastomer, 38-50 parts of tackifying resin, 15-25 parts of plasticizer, 3-5 parts of low temperature auxiliary agent and 0.5-1.0 part of antioxidant.

3. The hot melt pressure sensitive adhesive according to claim 1, characterized in that The thermoplastic elastomer includes at least one of SIS, SBS and SSBR.

4. The hot melt pressure sensitive adhesive according to claim 3, characterized in that The melt flow index of the SIS is 8 to 35 g / 10 min.

5. The hot melt pressure sensitive adhesive according to claim 3 or 4, characterized in that The diblock content of the SIS is 15-90%, and the block ratio of the SIS is (15-25): (85-75).

6. The hot melt pressure sensitive adhesive according to claim 1, characterized in that The tackifying resin includes at least one of terpene resin, petroleum resin, rosin glycerol ester, rosin pentaerythritol ester and rosin modified resin.

7. The hot melt pressure sensitive adhesive according to claim 1, characterized in that The plasticizer includes at least one of naphthenic oil, PE wax, polyisoprene and polyisobutylene.

8. The hot melt pressure sensitive adhesive according to claim 1, characterized in that The low temperature auxiliary agent is aliphatic hydrocarbon synthetic oil.

9. The method for preparing the hot melt pressure sensitive adhesive according to any one of claims 1 to 8, comprising: Thermoplastic elastomer, tackifying resin, plasticizer, low temperature auxiliary agent and antioxidant are mixed to obtain hot melt pressure sensitive adhesive.

10. Use of the hot melt pressure sensitive adhesive according to any one of claims 1 to 8 or the hot melt pressure sensitive adhesive prepared by the preparation method according to claim 9 in low temperature self-adhesive labels.