Oil-seepage-resistant and removable hot melt adhesive and preparation method thereof

Abstract

The invention relates to the technical field of hot melt adhesives, and discloses an oil-seepage-resistant and removable hot melt adhesive and a preparation method thereof.The hot melt adhesive is prepared from naphthenic oil, a moistening agent, SIS rubber, SBS rubber and tackifying resin; the wetting agent is polyethyleneimine, and the tackifying resin is hydrogenated petroleum resin. Polyethyleneimine molecules contain amino groups and vinyl groups, so that polyethyleneimine has polarity and hydrophobicity at the same time, the oil seepage resistance of the hot melt adhesive can be improved, and the removable performance of the hot melt adhesive can be improved. According to the preparation method of the hot melt adhesive, provided by the invention, the manufacturing cost of the oil-seepage-resistant and removable hot melt adhesive can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hot melt adhesives, and in particular to an oil-resistant and removable hot melt adhesive and a preparation method thereof. Background Art

[0002] With the development of the automotive industry and personal electronic products, hot melt adhesives are widely used in the packaging of automotive interiors and electronic products.

[0003] When the hot melt adhesive is used for a long time or the ambient temperature is high, the ingredients in the hot melt adhesive will penetrate into the bonding surface of the hot melt adhesive, which is commonly known as oil seepage, causing the bonding strength of the hot melt adhesive to decrease or even lose its bonding effect and fall off.

[0004] At the same time, in order to facilitate the maintenance and replacement of parts, the removability of hot melt adhesive is also a necessary performance indicator.

[0005] Therefore, it is difficult to balance and take into account the oil permeation resistance and removability of the hot melt adhesive in the prior art. Summary of the invention

[0006] In view of the above problems, the first object of the present invention is to provide an oil-proof and removable hot melt adhesive to solve the problem that the oil-proof performance and removability of the hot melt adhesive in the prior art are difficult to balance and take into account.

[0007] A second objective of the present invention is to provide a method for preparing a hot melt adhesive to reduce the manufacturing cost of the oil-resistant and removable hot melt adhesive.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A hot melt adhesive that is oil-resistant and removable, the raw materials of the hot melt adhesive comprising:

[0010] Naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin;

[0011] The lubricant is polyethyleneimine, and the tackifying resin is hydrogenated petroleum resin.

[0012] Specifically, calculated by mass percentage, the raw materials of the hot melt adhesive include:

[0013] Naphthenic oil 10-25%, lubricant 10-20%, SIS rubber 10-35%, SBS rubber 10-35%, tackifying resin 28-48% and antioxidant 0.1-1%.

[0014] Preferably, the number average molecular weight of the polyethyleneimine is 600-1200 g / mol; the pH value is 10-13; the density at 20°C is 1.03 g / cm 3; The water content is 0.4%-1.2%; the content of monomer ethyleneimine is 0.6-1.2ppm.

[0015] Preferably, the SIS rubber has a styrene content of 12-18 wt%; a diblock content of 35-45 wt%; a melt flow rate of 20-30 g / 10 min; a viscosity of 25% solution of 500-1500 cps; a tensile strength of 8-21.5 MPa; and an elongation at break of 1000%-1500%.

[0016] The SBS rubber has a styrene content of 35-45wt%, a melt flow rate of 0.1-5g / 10min, a tensile strength of 20-38MPa, a breaking elongation of 600%-1800%, and a Shore hardness of 85-95A / 10 seconds.

[0017] Preferably, the tackifying resin has a softening point of 90-120°C and a number average molecular weight of 200-600 g / mol;

[0018] The antioxidant is at least one of the antioxidant 1010 and the antioxidant 168 .

[0019] Furthermore, the present invention provides a method for preparing a hot melt adhesive, which is used to prepare the above-mentioned oil-resistant and removable hot melt adhesive, comprising the following steps:

[0020] S1) weighing naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin respectively according to the formula ratio, then adding antioxidant, naphthenic oil and lubricant into a container, and continuously stirring until the materials are uniformly mixed to obtain a mixed solution;

[0021] S2) adding SIS rubber and SBS rubber to the mixed solution in sequence, and continuously stirring until the rubber material is completely dissolved, to obtain a rubber solution;

[0022] S3) adding tackifying resin to the stirred rubber solution in portions, and continuing stirring until the tackifying resin is completely dissolved, thereby obtaining the oil-resistant and removable hot melt adhesive.

[0023] Preferably, in steps S1) to S3), the stirring and mixing temperature of the materials is 120-190°C.

[0024] Preferably, in step S1), the stirring time after adding the material is 5-20 minutes;

[0025] In step S2) and step S3), the stirring time after adding the materials is 20-90 minutes.

[0026] Preferably, the viscosity of the oil-resistant and removable hot melt adhesive is 5000-7500 cps.

[0027] The beneficial effects of the above technical solution of the present invention are as follows: the oil-penetration-resistant and removable hot melt adhesive uses polyethyleneimine as a lubricant and hydrogenated petroleum resin as a tackifying resin. The polyethyleneimine molecules contain amino groups and vinyl groups and have polarity and hydrophobicity, which can improve the compatibility of the system, reduce the formation of channels and gaps in the system that can be penetrated by oil molecules, and improve the oil-penetration resistance of the hot melt adhesive; the polyethyleneimine molecules can provide good wettability and dispersibility for the hot melt adhesive, and can also improve the removability of the hot melt adhesive.

[0028] Furthermore, the preparation method of the hot melt adhesive proposed in the present invention has the advantages of simple process, simple production equipment and low manufacturing cost. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0030] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0031] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

[0032] A hot melt adhesive that is oil-resistant and removable, the raw materials of the hot melt adhesive comprising:

[0033] Naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin;

[0034] The lubricant is polyethyleneimine, and the tackifying resin is hydrogenated petroleum resin.

[0035] The present invention provides an oil-penetration-resistant and removable hot melt adhesive, which uses polyethyleneimine as a lubricant and hydrogenated petroleum resin as a tackifying resin. The polyethyleneimine molecule contains amino groups and vinyl groups, wherein the amino groups are polar groups and the vinyl groups are hydrophobic groups, so that the polyethyleneimine has both polarity and hydrophobicity, and can achieve good compatibility and close combination with cyclohexane oil, SIS rubber and SBS rubber, and can reduce the formation of channels and gaps in the system that are penetrated by oil molecules, thereby improving the oil-penetration-resistant performance of the hot melt adhesive; the polyethyleneimine molecules containing polar groups and hydrophobic groups can provide good wettability and dispersibility for the hot melt adhesive, so that the hot melt adhesive can be more evenly bonded to the surface of a substrate to form a continuous and complete adhesive layer, and reduce defects and pores in the adhesive layer, thereby improving the removable performance of the hot melt adhesive.

[0036] Specifically, calculated by mass percentage, the raw materials of the hot melt adhesive include:

[0037] Naphthenic oil 10-25%, lubricant 10-20%, SIS rubber 10-35%, SBS rubber 10-35%, tackifying resin 28-48% and antioxidant 0.1-1%.

[0038] Naphthenic oil mainly plays a role in adjusting the flexibility and fluidity of hot melt adhesive. If the amount of naphthenic oil is too little, the hot melt adhesive will become hard and brittle, resulting in a decrease in peel strength, making it difficult to fully fill the microscopic pores on the surface of the substrate, and the contact area with the substrate will be reduced. On the contrary, if the amount of naphthenic oil is too much, the hot melt adhesive will be too soft and will flow and deform before it is completely cured.

[0039] Adding an appropriate proportion of polyethyleneimine (PEI) as a lubricant can interact with the various components in the system and enhance the cohesion of the hot melt adhesive, thereby improving the tensile strength and oil permeation resistance of the hot melt adhesive. If the amount of polyethyleneimine is too much, excessive cross-linking or aggregation may occur, resulting in stress concentration, which will reduce the tensile strength of the hot melt adhesive; it may even make the structure of the hot melt adhesive more rigid and reduce the elongation of the hot melt adhesive. Conversely, if the amount of polyethyleneimine is too little, the anti-oil permeation performance of the hot melt adhesive will not be improved enough.

[0040] SIS rubber is a styrene-isoprene block copolymer, and SEB rubber is a styrene-butadiene copolymer. If the amount of SIS rubber and SBS rubber is too little, the cohesion of the hot melt adhesive will deteriorate, the adhesive layer will easily break during the peeling process, the peeling strength will be reduced, and the residue after peeling will increase, affecting the removability of the hot melt adhesive. If the amount of SIS rubber and SBS rubber is too much, the hot melt adhesive will become too elastic and relatively insufficient in viscosity, which will also reduce the adhesion between the hot melt adhesive and the substrate, resulting in reduced peeling strength.

[0041] If the amount of tackifying resin is too little, the viscosity of the hot melt adhesive will be reduced. Although it will improve the residual adhesive of the hot melt adhesive on the substrate, it will cause the hot melt adhesive to be loosely bonded to the substrate. If the amount of tackifying resin is too much, the viscosity of the hot melt adhesive will be enhanced, and the peel strength may be too large, making the removability of the hot melt adhesive worse and increasing the residual adhesive.

[0042] If the amount of antioxidant used is too little, the hot melt adhesive will easily be oxidized and aged during storage and use.

[0043] Preferably, the number average molecular weight of the polyethyleneimine is 600-1200 g / mol; the pH value is 10-13; the density at 20°C is 1.03 g / cm 3 ; The water content is 0.4%-1.2%; The content of monomer ethyleneimine is 0.6-1.2ppm;

[0044] Preferably, the SIS rubber has a styrene content of 12-18 wt%; a diblock content of 35-45 wt%; a melt flow rate of 20-30 g / 10 min; a viscosity of 25% solution of 500-1500 cps; a tensile strength of 8-21.5 MPa; and an elongation at break of 1000%-1500%.

[0045] The SBS rubber has a styrene content of 35-45wt%; a melt flow rate of 0.1-5g / 10min; a tensile strength of 20-38MPa; an elongation at break of 600%-1800%; and a Shore hardness of 85-95A / 10 seconds.

[0046] Preferably, the tackifying resin has a softening point of 90-120°C and a number average molecular weight of 200-600 g / mol;

[0047] The antioxidant is at least one of the antioxidant 1010 and the antioxidant 168 .

[0048] Furthermore, the present invention provides a method for preparing a hot melt adhesive, which is used to prepare the above-mentioned oil-resistant and removable hot melt adhesive, comprising the following steps:

[0049] S1) weighing naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin respectively according to the formula ratio, then adding antioxidant, naphthenic oil and lubricant into a container, and continuously stirring until the materials are uniformly mixed to obtain a mixed solution;

[0050] S2) adding SIS rubber and SBS rubber to the mixed solution in sequence, and continuously stirring until the rubber material is completely dissolved, to obtain a rubber solution;

[0051] S3) adding tackifying resin to the stirred rubber solution in portions, and continuing stirring until the tackifying resin is completely dissolved, thereby obtaining the oil-resistant and removable hot melt adhesive.

[0052] The preparation method of the hot melt adhesive of the present invention has the advantages of simple process, simple production equipment and low manufacturing cost.

[0053] Preferably, in steps S1) to S3), the stirring and mixing temperature of the materials is 120-190°C.

[0054] At 120-190°C, the lubricant of polyethyleneimine is conducive to reacting with impurities containing aldehyde or ketone groups in the system, and the gas generated in the reaction process is discharged to the outside, avoiding bubble defects inside the prepared hot melt adhesive, thereby preventing the hot melt adhesive from generating defects and pores during use.

[0055] Preferably, in step S1), the stirring time after adding the material is 5-20 minutes;

[0056] In step S2) and step S3), the stirring time after adding the materials is 20-90 minutes.

[0057] Mix the materials evenly and dissolve completely by continuous stirring.

[0058] The preferred naphthenic oil is Sinopec KN4010, and the preferred lubricant is BASF FG polyethyleneimine, styrene-isoprene block copolymer preferably uses Polysun SIS-1140, styrene-butadiene copolymer preferably uses Jinhai JH-7401SBS rubber, tackifying resin preferably uses Jinhai JH-6100 hydrogenated petroleum resin, antioxidants preferably use 1:1 Lianlong antioxidant 1010 and Lianlong auxiliary antioxidant 168.

[0059] Preferably, the viscosity of the oil-resistant and removable hot melt adhesive is 5000-7500 cps.

[0060] The viscosity of the prepared hot melt adhesive is controlled to be 5000-7500 cps, which can ensure the use effect of the hot melt adhesive.

[0061] Examples 1-3 and Comparative Examples 1-4

[0062] 1. According to the raw material ratio in Table 1, the hot melt adhesives of Examples 1-3 and Comparative Examples 1-4 were prepared in the following steps:

[0063] S1) according to the raw material ratio of Table 1, naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin are weighed respectively, and then antioxidant, naphthenic oil and lubricant are added in a container, and stirring is continued until the materials are uniformly mixed to obtain a mixed solution;

[0064] S2) adding SIS rubber and SBS rubber to the mixed solution in sequence, and continuously stirring until the rubber material is completely dissolved, to obtain a rubber solution;

[0065] S3) adding tackifying resin to the stirred rubber solution in portions, and continuing stirring until the tackifying resin is completely dissolved, thereby obtaining the oil-resistant and removable hot melt adhesive;

[0066] In steps S1) to S3), the stirring and mixing temperature of the materials is 120-190°C;

[0067] In step S1), the stirring time after adding the material is 5-20 minutes;

[0068] In step S2) and step S3), the stirring time after adding the materials is 20-90 minutes.

[0069] In the above preparation process, the naphthenic oil is preferably Sinopec KN4010, and the lubricant is preferably BASF FG polyethyleneimine, styrene-isoprene block copolymer preferably uses Polysun SIS-1140, styrene-butadiene copolymer preferably uses Jinhai JH-7401SBS rubber, tackifying resin preferably uses Jinhai JH-6100 hydrogenated petroleum resin, antioxidants preferably use 1:1 Lianlong antioxidant 1010 and Lianlong auxiliary antioxidant 168.

[0070] 2. Performance Testing

[0071] 2.1 The peel strength of the steel plates and PE plates at 180° of Examples 1-3 and Comparative Examples 1-4 was tested according to GB / T 2792-2014, and the annular initial adhesion of the steel plates of Examples 1-3 and Comparative Examples 1-4 was tested according to GB / T 31125-2014. The test results are shown in Table 1.

[0072] 2.2 The hot melt adhesives of Examples 1-3 and Comparative Examples 1-4 were melted at the same temperature and coated on PET films with the same amount of adhesive to obtain hot melt adhesive tapes. The hot melt adhesive tapes were then cut into the same specifications and pasted on corrugated cardboards. The corrugated cardboards were then placed in an environment of 75°C for 8, 24, 32 and 48 hours, respectively, and the oil penetration of each test sample on the corrugated cardboard was observed to evaluate the oil penetration resistance of Examples 1-3 and Comparative Examples 1-4. The test results are shown in Table 1.

[0073] 2.3 The hot melt adhesives of Examples 1-3 and Comparative Examples 1-4 were melted at the same temperature and coated on PET film with the same amount of adhesive to obtain hot melt adhesive tapes. The hot melt adhesive tapes of each test sample were then cut into the same specifications and respectively pasted on the surfaces of PP, PE, synthetic rubber, metal plates, glass, thermal paper, coated paper, A4 paper, corrugated cardboard, non-woven fabrics and leather. After being left at room temperature for 7 days, the hot melt adhesive tapes were torn off and the adhesive film residue on the substrate was observed. The test results are shown in Table 1.

[0074] Table 1 Raw material ratios and test results of Examples 1-3 and Comparative Examples 1-4

[0075]

[0076]

[0077] From the test results in Table 1, we can see that:

[0078] In Example 1-3, the addition of polyethyleneimine significantly improves the peel strength between the hot melt adhesive and the steel plate and the PE plate. This is because polyethyleneimine works synergistically with other components in the adhesive to optimize the cohesive force of the adhesive itself, so that it can maintain good integrity when peeled under force and is not easily torn; at the same time, polyethyleneimine adjusts the contact state between the adhesive and the surface of the plate, not simply enhancing the adhesion, but at the microscopic level, allowing the adhesive to fit the surface of the plate more evenly and tightly, forming a stable and flat bonding interface. When peeling is required, this structure not only ensures the firmness of the bond, but also can be separated in an orderly manner under the action of external force, without excessive residue.

[0079] In terms of initial adhesion, the increase in the ring adhesion value of the steel plate shows that polyethyleneimine plays a key role in improving the initial adhesion performance of the hot melt adhesive. It enables the adhesive to interact with the steel plate surface quickly and closely at the moment of contact with the steel plate, and by adjusting the rheological properties of the adhesive, it can spread and adhere to the steel plate surface better in the initial stage, thereby improving the ring adhesion.

[0080] In terms of oil seepage resistance, Examples 1-3 have been placed for different lengths of time and have shown excellent oil seepage resistance. After 48 hours at 75°C, they can still maintain a small amount of oil seepage or no oil seepage. In contrast, Comparative Examples 1-4 performed poorly, with a small amount of oil seepage starting after 8 hours, a large amount of oil seepage after 24 hours, and a large amount of oil seepage until 48 hours. This is because polyethyleneimine is added to Examples 1-3, which can optimize the internal structure of the hot melt adhesive, make the components more tightly bonded, effectively fill possible tiny pores, and prevent oil from seeping out, thereby greatly improving the oil seepage resistance; while Comparative Examples 1-4 do not add polyethyleneimine, and the adhesive structure is relatively loose, which cannot resist the seepage of oil at high temperatures.

[0081] As for the removable performance, it can be seen from the residual glue performance test results that when facing a variety of substrate materials, such as PP, PE, synthetic rubber, metal plate, glass, thermal paper, coated paper, A4 paper, corrugated cardboard, non-woven fabrics, and leather, Examples 1-3 only have no residual glue or a small amount of residual glue. However, Comparative Examples 1-4 show more residual glue on a variety of substrates. This is because the stable bonding interface constructed with the participation of polyethyleneimine provides sufficient firmness during the bonding process. When external force is applied, due to the interfacial flatness of the adhesive surface and the optimization of the internal structure of the adhesive, the adhesive can be relatively completely separated from the substrate and is not easy to remain; while the comparative example lacks this regulatory effect of polyethyleneimine, adheres too firmly to the substrate and lacks a mechanism for orderly separation, making it difficult to achieve a good removable effect.

[0082] In summary, the oil-penetration-resistant and removable hot melt adhesive uses polyethyleneimine as a lubricant and hydrogenated petroleum resin as a tackifying resin. The polyethyleneimine molecules contain amino and vinyl groups and are polar and hydrophobic, which can improve the compatibility of the system and reduce the formation of channels and gaps in the system that can be penetrated by oil molecules, thereby improving the oil-penetration resistance of the hot melt adhesive. The polyethyleneimine molecules can provide good wettability and dispersibility for the hot melt adhesive and can also improve the removability of the hot melt adhesive.

[0083] Furthermore, the preparation method of the hot melt adhesive proposed in the present invention has the advantages of simple process, simple production equipment and low manufacturing cost.

[0084] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the scope of protection of the present invention.

Claims

1. A hot melt adhesive that is oil-resistant and removable, characterized in that: The raw materials of the hot melt adhesive include: Naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin; The lubricant is polyethyleneimine, and the tackifying resin is hydrogenated petroleum resin.

2. The oil-resistant and removable hot melt adhesive according to claim 1, characterized in that: Calculated by mass percentage, the raw materials of the hot melt adhesive include: Naphthenic oil 10-25%, lubricant 10-20%, SIS rubber 10-35%, SBS rubber 10-35%, tackifying resin 28-48% and antioxidant 0.1-1%.

3. The oil-resistant and removable hot melt adhesive according to claim 1, characterized in that: The pour point of the naphthenic oil is -25 to -10°C; the flash point is 200-240°C; the density at 20°C is 850-950 kg / m 3 ; The viscosity constant is 0.820-0.850; the refractive index at 20°C is 1.45-1.52; the aniline point is 90-110°C; the CN in the carbon type analysis is greater than 40%.

4. The oil-resistant and removable hot melt adhesive according to claim 1, characterized in that: The number average molecular weight of the polyethyleneimine is 600-1200 g / mol; the pH value is 10-13; the density at 20°C is 1.03 g / cm 3 ; The water content is 0.4%-1.2%; the content of monomer ethyleneimine is 0.6-1.2ppm.

5. The oil-resistant and removable hot melt adhesive according to claim 1, characterized in that: The SIS rubber has a styrene content of 12-18 wt %; a diblock content of 35-45 wt %; a melt flow rate of 20-30 g / 10 min; a viscosity of 25% solution of 500-1500 cps; a tensile strength of 8-21.5 MPa; and an elongation at break of 1000%-1500%; The SBS rubber has a styrene content of 35-45wt%, a melt flow rate of 0.1-5g / 10min, a tensile strength of 20-38MPa, a breaking elongation of 600%-1800%, and a Shore hardness of 85-95A / 10 seconds.

6. The oil-resistant and removable hot melt adhesive according to claim 1, characterized in that: The tackifying resin has a softening point of 90-120°C and a number average molecular weight of 200-600 g / mol; The antioxidant is selected from at least one of the antioxidant 1010 and the antioxidant 168 .

7. A method for preparing a hot melt adhesive, characterized in that: The method for preparing the oil-resistant and removable hot melt adhesive according to any one of claims 1 to 6 comprises the following steps: S1) weighing naphthenic oil, lubricant, SIS rubber, SBS rubber and tackifying resin respectively according to the formula ratio, then adding antioxidant, naphthenic oil and lubricant into a container, and continuously stirring until the materials are uniformly mixed to obtain a mixed solution; S2) adding SIS rubber and SBS rubber to the mixed solution in sequence, and continuously stirring until the rubber material is completely dissolved, to obtain a rubber solution; S3) adding tackifying resin to the stirred rubber solution in portions, and continuing stirring until the tackifying resin is completely dissolved, thereby obtaining the oil-resistant and removable hot melt adhesive.

8. The method for preparing the hot melt adhesive according to claim 5, characterized in that: In steps S1) to S3), the stirring and mixing temperature of the materials is 120-190°C.

9. The method for preparing the hot melt adhesive according to claim 5, characterized in that: In step S1), the stirring time after adding the material is 5-20 minutes; In step S2) and step S3), the stirring time after adding the materials is 20-90 minutes.

10. The method for preparing the hot melt adhesive according to claim 5, characterized in that: The viscosity of the prepared oil-resistant and removable hot melt adhesive is 5000-7500 cps.

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