PET bottle labeling hot melt adhesive and preparation process thereof

Abstract

The present application relates to the technical field of hot melt adhesive, especially to the field of IPC C 09J7, more particularly to a PET bottle labeling hot melt adhesive and a preparation process thereof.The PET bottle labeling hot melt adhesive is prepared from the following raw materials in parts by weight: thermoplastic elastomer 20-70 parts, tackifier 30-95 parts, softening agent 10-35 parts, and anti-aging agent 0.05-2 parts.The prepared PET bottle labeling hot melt adhesive has good initial adhesion, short open time, no stringing, high shear strength, good high and low temperature resistance, and is non-toxic and harmless, and is especially suitable for PET bottles such as oil bottles, vinegar bottles and soy sauce bottles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hot melt adhesive, especially to the field of IPC C 09J7, and more particularly to a PET bottle labeling hot melt adhesive and a preparation process thereof. BACKGROUND

[0002] For PET bottle labeling, some enterprises do not use glue and directly use adhesive labels for labeling, but the comprehensive performance of the adhesive label is poor, and the high and low temperature resistance is not good, so most enterprises use water-based glue for labeling. However, the water-based glue has a slow drying speed, low machine efficiency, and seriously affects the production.

[0003] In the prior art, a patent application file with the application publication number CN1314773A discloses a method for preparing a water-resistant high-speed labeling adhesive by intercalating casein and montmorillonite, and a labeling adhesive with high water resistance and strong enzyme hydrolysis stability is prepared. However, the initial adhesion is not high, and the stability at low temperature is poor.

[0004] A patent application file with the application publication number CN111471430A discloses a labeling adhesive for glass bottles and a preparation method thereof. The prepared labeling adhesive has good labeling effect on the surface of the glass bottle, fast drying time, and no stringing. However, the performance on the PET bottle is general, and the shear strength is low.

[0005] In recent years, some domestic enterprises have introduced hot melt adhesive labeling equipment, but the effect of the labeling hot melt adhesive is generally poor, especially the low temperature resistance in winter, which is prone to label warping, and the stringing phenomenon is prone to occur in summer. Therefore, it is necessary to develop a hot melt adhesive with good initial adhesion, short open time, no stringing, high shear strength, and good high and low temperature resistance for PET bottle labeling. SUMMARY

[0006] To solve the above problems, the present application provides a PET bottle labeling hot melt adhesive, and the preparation raw materials include, by weight: 20-70 parts of a thermoplastic elastomer, 30-95 parts of an adhesion promoter, 10-35 parts of a softening agent, and 0.05-2 parts of an antioxidant.

[0007] Preferably, the thermoplastic elastomer is one or more of styrene-based elastomers, silicone-based elastomers, olefin-based elastomers, vinyl chloride-based elastomers, diene-based elastomers, organic fluorine-based elastomers, amide-based elastomers, urethane-based elastomers, and ethylene-based elastomers; and further preferably, the thermoplastic elastomer is a styrene-based elastomer.

[0008] Preferably, the styrene-based elastomer is one or more of styrene-butadiene-styrene (SBS) block copolymer and styrene-isoprene-styrene (SIS); and further preferably, the styrene-based elastomer is SBS block copolymer and SIS block copolymer.

[0009] Preferably, the weight ratio of the SBS block copolymer and the SIS block copolymer is 1:(0.5-5); further preferably, 1:2.

[0010] Preferably, the SBS block copolymer is a hydrogenated SBS block copolymer.

[0011] Preferably, the hydrogenated SBS block copolymer has a styrene content of 20-40wt%, and a viscosity of 500-2000mPa-s in 20wt% toluene solution at 25°C; further preferably, the hydrogenated SBS block copolymer has a styrene content of 30wt%, and a viscosity of 1700mPa-s in 20wt% toluene solution at 25°C.

[0012] Applicants have found that the use of SBS block copolymer as thermoplastic elastomer can improve the viscosity and high temperature resistance of PET bottle labeling hot melt adhesive. This is probably because SBS block copolymer is a block copolymer composed of thermoplastic resin and soft elastomer, which has high elasticity and thermoplastic processability, and the crosslinked network structure formed by the hard segment and soft segment increases the viscosity of PET bottle labeling hot melt adhesive. However, its viscosity is low, and the unsaturated bond in its molecular chain makes it poor in heat aging resistance. Applicants have unexpectedly found that the use of hydrogenated SBS block copolymer with a styrene content of 20-40wt% and a viscosity of 500-2000mPa-s in 20wt% toluene solution at 25°C for preparing PET bottle labeling hot melt adhesive can not only improve the high temperature resistance of PET bottle labeling hot melt adhesive, but also improve the initial tack of PET bottle labeling hot melt adhesive. This is probably because the hydrogenation reaction converts the unsaturated bond in SBS block copolymer into a saturated bond, thereby improving the stability of PET bottle labeling hot melt adhesive, and on the other hand, the low content of styrene increases the viscosity of PET bottle labeling hot melt adhesive. However, excessive viscosity is not suitable for PET bottle hot melt adhesive, which can cause the adhesive to be stringy and have a long drying time. And high content of styrene can make PET bottle hot melt adhesive brittle, affecting its peel strength. Therefore, the use of hydrogenated SBS block copolymer with a styrene content of 20-40wt% and a viscosity of 500-2000mPa-s in 20wt% toluene solution at 25°C can improve the initial tack of PET bottle labeling hot melt adhesive, while also improving the curing time and high temperature resistance of PET bottle labeling hot melt adhesive, but the improvement in viscosity is limited, and it does not have good processing performance.

[0013] In some preferred embodiments, the hydrogenated SBS block copolymer can be commercially available, such as YH 502 produced by Hunan Yuehua Chemical Co., Ltd.

[0014] Preferably, the SIS block copolymer has a styrene content of 10-30wt% and a melt index of 5-20g / 10min; more preferably, the SIS block copolymer has a styrene content of 15wt% and a melt index of 7-17g / 10min.

[0015] The applicant surprisingly found that the use of SBS block copolymer and SIS block copolymer with a weight ratio of 1:(0.5-5) as the thermoplastic elastomer can further improve the viscosity and peel strength of the PET bottle labeling hot melt adhesive. This may be due to the fact that the SBS block copolymer can combine with the soft segment polyisoprene in the SIS block copolymer to form an elastic network, and the SIS block copolymer has multiple side methyl structures, which can provide strong adhesion for the pressure-sensitive hot melt adhesive, thereby enabling the addition of SIS block copolymer to improve the viscosity of the PET bottle labeling hot melt adhesive. In addition, the use of SIS block copolymer with a styrene content of 10-30wt% and a melt index of 5-20g / 10min can improve the processing performance and high transparency of the PET bottle labeling hot melt adhesive, making it more suitable for application in PET bottle labeling hot melt adhesive. However, SIS block copolymer is expensive and mostly imported, resulting in high use cost. Therefore, the use of SBS block copolymer and SIS block copolymer with a weight ratio of 1:(0.5-5) as the thermoplastic elastomer not only can further improve the viscosity and peel strength of the PET bottle labeling hot melt adhesive, but also can save cost and have high economic benefits. However, the thermoplastic elastomer itself does not have adhesion, so other ingredients must be added to increase the flowability and adhesion to PET bottles and labels of the PET bottle labeling hot melt adhesive.

[0016] In some preferred embodiments, the SIS block copolymer can be commercially available, such as YH 1106 produced by Hunan Yuehua Chemical Co., Ltd.

[0017] Preferably, the tackifier is one or more of polyterpene resins, hydrocarbon resins, rosin resins, phenolic resins, xylene resins, and terpene phenolic resins; more preferably, the tackifier is hydrocarbon resins and rosin resins.

[0018] Preferably, the weight ratio of the hydrocarbon resins and rosin resins is 1:(1-5); more preferably, the weight ratio is 5:7.

[0019] Preferably, the hydrocarbon resins are one or more of aliphatic hydrocarbon resins (C5), alicyclic hydrocarbon resins (DCPD), aromatic hydrocarbon resins (C9), aliphatic / aromatic copolymer hydrocarbon resins (C5 / C9), C5 hydrogenated hydrocarbon resins, and C9 hydrogenated hydrocarbon resins; more preferably, the hydrocarbon resins are C5 hydrogenated hydrocarbon resins.

[0020] Preferably, the softening point of the C5 hydrogenated hydrocarbon resin is 90-110℃, and the melt viscosity at 200℃ is 150-250cps; further preferably, the softening point of the C5 hydrogenated hydrocarbon resin is 97-104℃, and the melt viscosity is 190-200cps.

[0021] In some preferred embodiments, the C5 hydrogenated hydrocarbon resin can be commercially available, such as LH-1100 produced by the supplier Shandong Luhua Energy Group Co., Ltd.

[0022] Preferably, the rosin resin is one or more of maleic rosin resin, hydrogenated rosin resin, polymerized rosin resin, and disproportionated rosin resin; further preferably, the hydrogenated rosin resin.

[0023] Preferably, the softening point of the hydrogenated rosin resin is 80-100℃, and the acid value is 3-15mgKOH / g; further preferably, the softening point of the hydrogenated rosin resin is 82-88℃, and the acid value is 5-10mgKOH / g.

[0024] In some preferred embodiments, the hydrogenated rosin resin can be commercially available, such as GA-85H produced by the supplier Japan Arakawa Co., Ltd.

[0025] The applicant surprisingly found that the aliphatic hydrocarbon resin and rosin resin with a weight ratio of 1:(1-5) can improve the stability and adhesion of the PET bottle labeling hot melt adhesive. This may be due to the fact that the aliphatic hydrocarbon resin has excellent compatibility with the SIS block copolymer and the SBS block copolymer, thereby improving the wettability of the PET bottle labeling hot melt adhesive to the substrate, so that the two can fully contact each other to improve the adhesion. However, the unsaturated bond in the hydrocarbon resin can affect the weather resistance of the PET bottle labeling hot melt adhesive, and the color of the adhesive is dark, which is not suitable for application in the PET bottle labeling PET bottle labeling hot melt adhesive. The applicant surprisingly found that the hydrogenated aliphatic hydrocarbon resin with a softening point of 90-110°C and a melt viscosity of 150-250 cps at 200°C can not only improve the adhesion of the PET bottle labeling hot melt adhesive, but also the color of the hydrogenated aliphatic hydrocarbon resin is lighter, which is suitable for application in the PET bottle labeling hot melt adhesive. In addition, the higher softening point also makes it exist in the system in the form of aggregate state, which improves the cohesion, so that the PET bottle labeling hot melt adhesive will not appear the situation of stringing. However, the single component tackifier has limited effect on the adhesion of the PET bottle labeling hot melt adhesive. The applicant surprisingly found that when the hydrogenated rosin resin with a softening point of 80-100°C and an acid value of 3-15 mgKOH / g is added, and the mass ratio of the hydrogenated aliphatic hydrocarbon resin and the hydrogenated rosin resin is 1:(1-5), the two can synergistically act on each other, which not only can improve the initial adhesion and peel strength of the PET bottle labeling hot melt adhesive with the SBS block copolymer and the SIS block copolymer as the matrix, but also can meet the requirements of the PET bottle labeling hot melt adhesive, and the rosin resin is cheap, which can improve the economic benefits of the PET bottle labeling hot melt adhesive.

[0026] Preferably, the softening agent is one or more of phthalate esters, white oil, liquid paraffin, naphthenic oil, polyethylene glycol, and fatty acid esters; further preferably, it is naphthenic oil.

[0027] Preferably, the naphthenic oil has a kinematic viscosity of 150-160 mm 2 / s at 40°C; further preferably, it is 158.1 mm 2 / s.

[0028] The applicant surprisingly found that adding a certain amount of naphthenic oil as a softening agent can improve the initial tack and peel strength of the PET bottle labeling hot melt adhesive. This may be because the naphthenic oil contains non-polar small molecules such as cyclopentane and cyclohexane, which can insert into the isoprene molecular segment in the thermoplastic elastomer to increase the distance between the molecules and weaken the interaction between the soft segments, thereby increasing the softness of the thermoplastic elastomer, improving the ability of the PET bottle labeling hot melt adhesive to wet the surface of the PET bottle, and further improving the peel strength and initial tack of the PET bottle labeling hot melt adhesive. However, if the amount of naphthenic oil added is too much, some non-polar small molecules will insert into the hard segment, affecting the cross-linking between the polar groups on the molecular chain of the hard segment, and the peel strength and initial tack of the PET bottle labeling hot melt adhesive will be sharply reduced. The applicant found that when the weight of the softening agent is 10-35% of the total weight of the PET bottle labeling hot melt adhesive, not only can the initial tack and peel strength of the PET bottle labeling hot melt adhesive be improved, but also the naphthenic oil is non-toxic and harmless, and is suitable for application in PET bottle labeling hot melt adhesives for oil bottles, vinegar bottles, and soy sauce bottles.

[0029] In some preferred embodiments, the softening agent can be commercially available, such as KN4010 produced by the supplier Guangdong Zhonghai Nanlian Energy Co., Ltd.

[0030] Preferably, the weight of the softening agent is 10-35% of the total weight of the PET bottle labeling hot melt adhesive; further preferably, 20%.

[0031] Preferably, the anti-aging agent is one or more of N-cyclohexyl-N'-phenyl-p-phenylenediamine, tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 2,2-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate; further preferably, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate.

[0032] Preferably, the weight ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid octadecyl ester and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate is 1:(0.5-3); further preferably, 1:1.5.

[0033] In some preferred embodiments, the beta-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester can be commercially available, such as produced by Tianjin Li'anlong New Material Co., Ltd. 1076.

[0034] In some preferred embodiments, the bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate can be commercially available, such as produced by Tianjin Li'anlong New Material Co., Ltd. 626.

[0035] The second aspect of the present application provides a preparation method of the PET bottle labeling hot melt adhesive as described above, comprising the following steps:

[0036] After mixing the thermoplastic elastomer, tackifier, softening agent and antioxidant are added, heated to 100-130℃ and protected by nitrogen, until the mixture is basically melted, then heated to 135-160℃, and the uniform transparent solution is obtained.

[0037] Beneficial effects:

[0038] 1. By selecting a hydrogenated SBS block copolymer with a styrene content of 20-40wt%, a viscosity of 500-2000mPa·s in a 20wt% toluene solution at 25℃, the initial adhesion of the PET bottle labeling hot melt adhesive can be improved, and the curing time and high temperature stability of the PET bottle labeling hot melt adhesive can also be improved, and the PET bottle labeling hot melt adhesive is not prone to stringing.

[0039] 2. By selecting a SIS block copolymer with a styrene content of 10-30wt% and a melt index of 5-20g / 10min, the processing performance and high transparency of the PET bottle labeling hot melt adhesive can be improved, making it more suitable for application in PET bottle labeling hot melt adhesive.

[0040] 3. By selecting SBS block copolymer and SIS block copolymer with a weight ratio of 1:(0.5-5) as the thermoplastic elastomer, not only can the viscosity and peel strength of the PET bottle labeling hot melt adhesive be further improved, but also can save costs, with high economic benefits.

[0041] 4. By selecting a hydrogenated aliphatic hydrocarbon resin with a softening point of 90-110℃ and a melt viscosity of 150-250cps at 200℃, not only can the adhesion of the PET bottle labeling hot melt adhesive be improved, but also the color of the hydrogenated aliphatic hydrocarbon resin is lighter, which is suitable for application in PET bottle labeling hot melt adhesive, and the PET bottle labeling hot melt adhesive is not prone to stringing.

[0042] 5. By adding hydrogenated rosin resin with softening point of 80-100 DEG C and acid value of 3-15 mgKOH / g, and the mass ratio of hydrogenated aliphatic hydrocarbon resin and hydrogenated rosin resin is 1:(1-5), not only can improve the initial adhesion and peel strength of PET bottle labeling hot melt adhesive with SBS block copolymer and SIS block copolymer as matrix, meet the demand of PET bottle labeling hot melt adhesive, and rosin resin is cheap, can improve the economic benefit of PET bottle labeling hot melt adhesive.

[0043] 6. By selecting naphthenic oil as softening agent, which is 10-35% of the total weight of PET bottle labeling hot melt adhesive, not only can improve the initial adhesion and peel strength of PET bottle labeling hot melt adhesive, and naphthenic oil is non-toxic and harmless, suitable for application in PET bottle labeling hot melt adhesive of oil bottle, vinegar bottle, soy sauce bottle and the like.

[0044] 7. The PET bottle labeling hot melt adhesive prepared by the application is not only suitable for PET bottles such as oil bottles, soybean oil bottles, vinegar bottles, soy sauce bottles and the like, but also suitable for carton sealing, paper product processing, flexible packaging, envelopes, textiles, cigarette glue and non-woven fabric fields. DETAILED DESCRIPTION

[0045] EMBODIMENT

[0046] EMBODIMENT 1

[0047] Embodiment 1 provides a kind of PET bottle labeling hot melt adhesive, preparation raw material includes by weight parts: thermoplastic elastomer 45 parts, tackifier 60 parts, softening agent 26.5 parts, antioxidant 1 part.

[0048] The thermoplastic elastomer is styrene-based elastomer.

[0049] The styrene-based elastomer is SBS block copolymer and SIS block copolymer.

[0050] The weight ratio of the SBS block copolymer and the SIS block copolymer is 1:2.

[0051] The SBS block copolymer is hydrogenated SBS block copolymer.

[0052] The styrene content in the hydrogenated SBS block copolymer is 30 wt%, and the viscosity in 20 wt% toluene solution at 25 DEG C is 1700 mPa·s.

[0053] The hydrogenated SBS block copolymer is purchased from the supplier Hunan Yuehua Chemical Co., Ltd. YH502 produced.

[0054] The styrene content in the SIS block copolymer is 15 wt%, and the melt index is 7-17 g / 10 min.

[0055] The SIS block copolymer is purchased from YH 1106 produced by Hunan Yuehua Chemical Co., Ltd.

[0056] The tackifier is a hydrocarbon resin and a rosin resin.

[0057] The weight ratio of the hydrocarbon resin and the rosin resin is 5:7.

[0058] The hydrocarbon resin is a C5 hydrogenated hydrocarbon resin.

[0059] The softening point of the C5 hydrogenated hydrocarbon resin is 97-104℃, and the melt viscosity is 190-200 cps.

[0060] The C5 hydrogenated hydrocarbon resin is purchased from LH-1100 produced by Shandong Luhua Energy Group Co., Ltd.

[0061] The rosin resin is a hydrogenated rosin resin.

[0062] The softening point of the hydrogenated rosin resin is 82-88℃, and the acid value is 5-10 mgKOH / g.

[0063] The hydrogenated rosin resin is purchased from GA-85H produced by Japan Arakawa Co., Ltd.

[0064] The softening agent is a naphthenic oil.

[0065] The kinematic viscosity of the naphthenic oil at 40℃ is 158.1 mm 2 / s.

[0066] The softening agent is purchased from KN4010 produced by Guangdong Zhonghai Nanlian Energy Co., Ltd.

[0067] The antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate.

[0068] The weight ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate is 1:1.5.

[0069] The β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate is purchased from 1076.

[0070] The bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate is purchased from 626.

[0071] The second aspect of the present application provides a preparation method of the PET bottle labeling hot melt adhesive as described above, comprising the following steps:

[0072] After the thermoplastic elastomer is mixed, tackifiers, softening agents and antioxidants are added, heated to 110°C and protected by nitrogen, until the mixture is melted, then heated to 150°C, and the uniform transparent solution is obtained.

[0073] Example 2

[0074] Example 2 provides a PET bottle labeling hot melt adhesive, and the specific implementation manner is the same as that in Example 1, and the difference lies in that the preparation raw materials include, by weight fraction, thermoplastic elastomer 30 parts, tackifier 30 parts, softening agent 10 parts, and antioxidant 0.05 parts.

[0075] The weight ratio of the SBS block copolymer and the SIS block copolymer is 2:1.

[0076] The weight ratio of the hydrocarbon resin and the rosin resin is 1:1.

[0077] The weight ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate and the bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate is 2:1.

[0078] Example 3

[0079] Example 3 provides a PET bottle labeling hot melt adhesive, and the specific implementation manner is the same as that in Example 1, and the difference lies in that the preparation raw materials include, by weight fraction, thermoplastic elastomer 60 parts, tackifier 45 parts, softening agent 20 parts, and antioxidant 0.5 parts.

[0080] The weight ratio of the SBS block copolymer and the SIS block copolymer is 1:5.

[0081] The weight ratio of the hydrocarbon resin and the rosin resin is 1:3.

[0082] The weight ratio of the β-(3,5-di-tert-butyl-4-hydroxyphenyl) octadecyl propionate and the bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate is 2:1.

[0083] Example 4

[0084] Example 4 provides a PET bottle labeling hot melt adhesive, and the specific implementation manner is the same as that in Example 1, and the difference lies in that the weight ratio of the hydrocarbon resin and the rosin resin is 2:1.

[0085] Example 5

[0086] Example 5 provides a PET bottle labeling hot melt adhesive, the specific implementation of the embodiment is same as example 1, the difference is that the weight fraction of the softening agent is 70 parts (about 40% of the total weight of the PET bottle labeling hot melt adhesive).

[0087] Performance test method

[0088] 1. Peel strength

[0089] The PET bottle labeling hot melt adhesive prepared in examples 1-5 is coated on a layer of PET, and another layer of PET is covered on it. After standing for 24 h, the peel strength is determined by using the national standard GB / T 2792-2014, and the results are recorded in Table 1.

[0090] 2. Initial tack

[0091] The initial tack of the PET bottle labeling hot melt adhesive prepared in examples 1-5 is tested by referring to GB / T 31125-2014, and the results are recorded in Table 1.

[0092] 3. Weather resistance

[0093] Low temperature resistance:

[0094] The PET bottle labeling hot melt adhesive prepared in examples 1-5 is coated on a label paper, and then pasted on the surface of a PET oil bottle. After standing for 24 h until complete adhesion, it is placed in an environment of-10℃ for 24 h, then taken out, and the paper label is torn off. Whether the paper label can be smoothly torn off is observed. If the label cannot be smoothly torn off, it is a label breakage. The breakage indicates that the peel strength between the labeling adhesive and the surface of the oil bottle is high, and the low temperature stability is good. The results are recorded in Table 1.

[0095] High temperature resistance:

[0096] The PET bottle labeling hot melt adhesive prepared in examples 1-5 is coated on a label paper, and then pasted on the surface of a PET oil bottle. After standing for 24 h until complete adhesion, it is placed in an environment of 70℃ for 24 h, then taken out, and the paper label is torn off. Whether the paper label can be smoothly torn off is observed. If the label cannot be smoothly torn off, it is a label breakage. The breakage indicates that the peel strength between the labeling adhesive and the surface of the oil bottle is high, and the high temperature stability is good. The results are recorded in Table 1.

[0097] 4. Open time

[0098] The open time of the PET bottle labeling hot melt adhesive prepared in examples 1-5 is determined by using HG / T 3716-2003, and the results are recorded in Table 1.

[0099] Table 1

[0100]

Claims

1. A hot melt adhesive for labeling PET bottles, characterized in that, The raw materials for preparation, by weight, include: 45 parts thermoplastic elastomer, 60 parts tackifier, 26.5 parts softener, and 1 part antioxidant; The thermoplastic elastomer is a styrene-based elastomer; The styrene-based elastomer is an SBS block copolymer and a SIS block copolymer; The weight ratio of the SBS block copolymer to the SIS block copolymer is 1:2; The SBS block copolymer is a hydrogenated SBS block copolymer; The hydrogenated SBS block copolymer has a styrene content of 30 wt% and a viscosity of 1700 mPa·s in a 20 wt% toluene solution at 25°C. The SIS block copolymer has a styrene content of 15 wt% and a melt index of 7-17 g / 10 min. The tackifier is a hydrocarbon resin and a rosin resin; The weight ratio of the hydrocarbon resin to the rosin resin is 5:7; The hydrocarbon resin is a C5 hydrogenated hydrocarbon resin; The C5 hydrogenated hydrocarbon resin has a softening point of 97-104℃ and a melt viscosity of 190-200cps. The rosin resin is a hydrogenated rosin resin; The hydrogenated rosin resin has a softening point of 82-88℃ and an acid value of 5-10 mgKOH / g. The softener is a naphthenic oil; The kinematic viscosity of the naphthenic oil at 40°C is 158.1 mm. 2 / s; The antioxidants are β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester and bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate ester; The weight ratio of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate ester is 1:1.

5.

2. A preparation process for a PET bottle labeling hot melt adhesive according to claim 1, characterized in that, Includes the following steps: After mixing the thermoplastic elastomers, add tackifiers, softeners, and antioxidants, heat to 100-130℃ and purge with nitrogen for protection until the mixture is basically melted, then raise the temperature to 135-160℃ and stir until the solution is uniform and transparent, which is the final product.

Images