Polypropylene sheet adhesive hot melt and method for preparing the same

Abstract

The present application relates to a kind of polypropylene sheet bonding hot melt adhesive and its preparation method.The polypropylene sheet bonding hot melt adhesive includes the following raw materials: polypropylene graft maleic anhydride, POE graft maleic anhydride and / or EVA graft maleic anhydride, polypropylene resin, polypropylene wax and / or polyethylene wax, terpene resin;The polypropylene graft maleic anhydride includes the low grafting rate polypropylene graft maleic anhydride with grafting rate of 0.8~1.2% and the high grafting rate polypropylene graft maleic anhydride with grafting rate of 3~5%.The hot melt adhesive of the present application meets the requirement of medical polypropylene bubble pack, and the adhesive has good compatibility, and the peeling performance is better.

Description

Technical Field

[0001] This invention belongs to the field of polyolefin resin technology, and specifically relates to a hot melt adhesive for bonding polypropylene sheets. Background Technology

[0002] Traditionally, solid pharmaceutical blister packaging uses a composite of polyvinyl chloride (PVC) sheets and aluminum foil. However, due to the inherently poor hygiene and environmental performance of PVC, polypropylene (PP), with its moisture barrier properties, is replacing PVC as a superior packaging material for solid pharmaceuticals. The PP solid pharmaceutical blister packaging technology involves thermoforming a polypropylene sheet into a blister, filling it with the solid pharmaceutical product, and then heat-pressing it to coated aluminum foil to form the blister packaging. For the bonding of polypropylene and aluminum foil, hot melt adhesive must be used according to pharmaceutical packaging requirements, and the peel strength must meet a minimum requirement of 7 N / 15 mm, according to relevant regulations. The heat-sealing temperature cannot be too high, otherwise it will cause deformation of the sheet; in principle, it should not exceed 150℃. Because pharmaceutical packaging is relatively fast, heat sealing also needs to be completed quickly; in principle, the heat-sealing time should not exceed 1 second. According to current pharmaceutical packaging technology requirements, the hot melt adhesive is applied to the aluminum foil; currently, the hot melt adhesive application amount for PVC sheets is 30 g / m². 2 Therefore, the amount of hot melt adhesive applied to polypropylene bonding aluminum foil should also be 30g / m². 2 This places high demands on the flow properties of hot melt adhesives during coating.

[0003] Chinese patent CN111154416 discloses a radiation-crosslinked polypropylene heat-shrinkable tape for anti-corrosion joints of submarine pipelines and its preparation method. The polypropylene hot melt adhesive components are disclosed as follows: maleic anhydride-grafted random copolymer polypropylene, maleic anhydride-grafted block copolymer polypropylene, maleic anhydride-grafted metallocene polyethylene, tackifying resin, antioxidant, etc., wherein the grafting rate of the maleic anhydride-grafted random copolymer polypropylene is 0.6–1.2%, and the grafting rate of the maleic anhydride-grafted block copolymer polypropylene is 0.8–1.2%. Chinese patent CN106010391 discloses a high-temperature resistant radiation-crosslinked... This invention relates to hot melt adhesives for polypropylene heat shrinkable tape, heat shrinkable tape, and their preparation methods. The hot melt adhesive comprises maleic anhydride-grafted polypropylene, maleic anhydride-grafted low-density polyethylene, maleic anhydride-grafted high-density polyethylene, modified thermoplastic elastomers, tackifying resins, and antioxidants. Chinese patent CN112852346 discloses a high-bonding-strength hot melt adhesive for polypropylene plastic honeycomb panels and its preparation method. This hot melt adhesive comprises maleic anhydride-grafted polyolefin elastomers, propylene-based polymers, polypropylene, styrene-based thermoplastic elastomers, ethylene propylene rubber, tackifiers, flowability enhancers, and functional additives. These hot melt adhesives are applied to the bonding of pipes and honeycomb panels, respectively, without the need for peeling. Summary of the Invention

[0004] The purpose of this invention is to provide a hot melt adhesive that can bond polypropylene sheets and aluminum foil, which has good compatibility and good peel performance.

[0005] To achieve the above objectives, the present invention provides a hot melt adhesive for bonding polypropylene sheets, comprising the following raw materials: polypropylene grafted maleic anhydride, ethylene-octene copolymer (POE) grafted maleic anhydride and / or ethylene-vinyl acetate copolymer (EVA) grafted maleic anhydride, polypropylene resin, polypropylene wax and / or polyethylene wax, and terpene resin; wherein the polypropylene grafted maleic anhydride comprises low grafting rate polypropylene grafted maleic anhydride with a grafting rate of 0.8-1.2% and high grafting rate polypropylene grafted maleic anhydride with a grafting rate of 3-5%.

[0006] The polypropylene sheet bonding hot melt adhesive of the present invention comprises polypropylene grafted maleic anhydride, which is propylene homopolymer grafted maleic anhydride and / or ethylene-propylene copolymer grafted maleic anhydride.

[0007] The polypropylene sheet bonding hot melt adhesive of the present invention comprises polypropylene grafted maleic anhydride with a high grafting rate of 3000-9000 g / mol and a molecular weight of 50000-80000 g / mol, in a mass ratio of 30:20 to 40:20.

[0008] The polypropylene sheet bonding hot melt adhesive of the present invention has a total grafting rate of maleic anhydride grafted onto the polypropylene of ≥2%.

[0009] The polypropylene sheet bonding hot melt adhesive of the present invention has a maleic anhydride grafting rate of ≤1% for POE grafted with maleic anhydride and / or EVA grafted with maleic anhydride.

[0010] The polypropylene sheet bonding hot melt adhesive of the present invention is wherein the polypropylene resin is homopolymer polypropylene, ethylene-propylene copolymer polypropylene or propylene-butadiene copolymer polypropylene, and the melt flow rate range is 2-30 g / 10 min.

[0011] The polypropylene sheet bonding hot melt adhesive of the present invention comprises, by weight, 50-60 parts of polypropylene grafted maleic anhydride, 5-10 parts of POE grafted maleic anhydride and / or EVA grafted maleic anhydride, 10-30 parts of polypropylene resin, 10-30 parts of polypropylene wax and / or polyethylene wax, and 5-7 parts of terpene resin.

[0012] The polypropylene sheet bonding hot melt adhesive of the present invention further includes 0.1 to 0.5 parts of antioxidant.

[0013] The polypropylene resin, polypropylene grafted maleic anhydride, ethylene-octene copolymer (POE) grafted maleic anhydride, ethylene-vinyl acetate copolymer (EVA) grafted maleic anhydride, polypropylene wax, polyethylene wax, and terpene resin described in this invention can be obtained by purchase or prepared by conventional preparation methods in the art.

[0014] This invention also discloses a method for preparing a hot melt adhesive for bonding polypropylene sheets: all raw materials are mixed in a high-speed mixer to form a mixture, the mixture is then added to a twin-screw extruder for extrusion, the water-cooled strands are then granulated in a granulator, and finally the granules are dried and packaged.

[0015] The preparation method of the polypropylene sheet bonding hot melt adhesive of the present invention uses a parallel twin-screw extruder with a length-to-diameter ratio of 30-60:1.

[0016] The preparation method of the polypropylene sheet bonding hot melt adhesive of the present invention uses a twin-screw extruder with an operating temperature of 130-240℃.

[0017] Beneficial effects of this invention:

[0018] The hot melt adhesive of this invention improves the compatibility of the hot melt adhesive by adding POE-grafted maleic anhydride and / or EVA-grafted maleic anhydride, and reduces the softening temperature of polypropylene-grafted maleic anhydride, thereby improving the heat-sealing bond strength and reducing the heat-sealing temperature. By controlling the grafting rate of polypropylene-grafted maleic anhydride, the bonding performance of the hot melt adhesive is improved, resulting in good peel performance.

[0019] The hot melt adhesive of this invention is a compound made of polypropylene grafted with maleic anhydride at different grafting rates, ethylene-octene copolymer (POE) grafted with maleic anhydride, and / or ethylene-vinyl acetate copolymer (EVA) grafted with maleic anhydride, and polypropylene resin. It meets the requirements for medical polypropylene blister packaging. Under process conditions where the heat-sealing temperature does not exceed 150°C and the heat-sealing time does not exceed 1 second, the heat-sealing bond strength between the polypropylene sheet and aluminum foil is greater than 7 N / 15 mm, exhibiting good compatibility and peel performance. During use, the hot melt adhesive can be pre-applied to pharmaceutical aluminum foil, then rolled up for storage and transportation, without sticking during storage and transportation. Attached Figure Description

[0020] Figure 1 The image shows a SEM image of the hot melt adhesive prepared in Example 1 after solvent etching.

[0021] Figure 2 The image shows a SEM image of the hot melt adhesive prepared in Example 2 after solvent etching.

[0022] Figure 3 The image shows a SEM image of the hot melt adhesive prepared in Example 3 after solvent etching.

[0023] Figure 4 The image shows a SEM image of the hot melt adhesive prepared in Example 4 after solvent etching.

[0024] Figure 5 The image shows a SEM image of the hot melt adhesive prepared in Example 5 after solvent etching.

[0025] Figure 6 The image shows a SEM image of the hot melt adhesive prepared in Comparative Example 1 after solvent etching.

[0026] Figure 7 The image shows a SEM image of the hot melt adhesive prepared in Comparative Example 2 after solvent etching.

[0027] Figure 8 The image shows the SEM image of the hot melt adhesive prepared in Comparative Example 3 after solvent etching. Detailed Implementation

[0028] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0029] Example 1

[0030] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0031] 30 parts of polypropylene resin (Lanzhou Petrochemical EP533N, ethylene-propylene copolymer, melt index 28g / 10min)

[0032] 30 parts of high-grafting-rate polypropylene grafted with maleic anhydride (Toyobo KE, 3.5% grafting rate, number average molecular weight 5000 g / mol)

[0033] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 1.2% grafting rate, number average molecular weight 50000 g / mol)

[0034] 5 parts of POE-grafted maleic anhydride (Nengzhiguang V series, 0.8% grafting rate)

[0035] 10 parts of polypropylene wax (Korea CS-53NC)

[0036] 5 parts of terpene resin (T100)

[0037] Antioxidant (1010) 0.1 parts

[0038] The overall grafting rate of maleic anhydride onto polypropylene was 2.4%.

[0039] Preparation method: The raw materials are mixed in a high-speed mixer for 3 minutes, and then the mixture is added to a parallel twin-screw extruder with a length-to-diameter ratio of 50:1 for further mixing, extrusion, and granulation. The operating temperature of the parallel twin-screw extruder is set as follows: die head 200℃, zone 1 130℃, zone 2 160℃, zone 3 200℃, zone 4 210℃, zone 5 220℃, zone 6 230℃, zone 7 230℃, zone 8 220℃, zone 9 220℃, and zone 10 220℃. Finally, the mixture is water-cooled, stretched, granulated, dried, and packaged to obtain the final product.

[0040] Example 2

[0041] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0042] 20 parts of polypropylene resin (Lanzhou Petrochemical RP260, ethylene-propylene copolymer, melt flow rate 8.0 g / 10 min)

[0043] 40 parts of high-graft-rate polypropylene grafted with maleic anhydride (Toyobo KE, 4% grafting rate, number average molecular weight 4500 g / mol)

[0044] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 0.8% grafting rate, number average molecular weight 80000 g / mol)

[0045] 10 parts of EVA grafted with maleic anhydride (35% vinyl acetate content, 0.1% grafting rate)

[0046] 10 parts of polyethylene wax (SCG Chemical LP0040p, Thailand)

[0047] 5 parts of terpene resin (T110)

[0048] Antioxidant (1076) 0.3 parts

[0049] The overall grafting rate of maleic anhydride onto polypropylene was 2.6%.

[0050] The preparation method is the same as in Example 1.

[0051] Example 3

[0052] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0053] 30 parts of polypropylene resin (Lanzhou Petrochemical RPB08I, propylene-butadiene copolymer, melt flow rate 8.0 g / 10 min)

[0054] 30 parts of high-grafting-rate polypropylene grafted with maleic anhydride (Toyobo KE, 3.0% grafting rate, number average molecular weight 9000 g / mol)

[0055] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 1.0% grafting rate, number average molecular weight 65000 g / mol)

[0056] Three parts of POE-grafted maleic anhydride (Nengzhiguang V series, 0.7% grafting rate)

[0057] Two portions of EVA grafted with maleic anhydride (35% vinyl acetate content, 0.1% grafting rate).

[0058] 10 parts of polypropylene wax (Clariant 2502)

[0059] 5 parts of terpene resin (TP1105)

[0060] Antioxidant (B215) 0.5 parts

[0061] The overall grafting rate of maleic anhydride onto polypropylene was 2.4%.

[0062] The preparation method is the same as in Example 1.

[0063] Example 4

[0064] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0065] 25 parts of polypropylene resin (Lanzhou Petrochemical H02M, homopolymer polypropylene, melt flow rate 2.0 g / 10 min)

[0066] 30 parts of high-graft-rate polypropylene grafted with maleic anhydride (Toyobo KE, 5% grafting rate, number average molecular weight 3000 g / mol)

[0067] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 0.8% grafting rate, number average molecular weight 80000 g / mol)

[0068] 5 parts of POE-grafted maleic anhydride (Nengzhiguang V series, 0.8% grafting rate)

[0069] 5 parts of EVA grafted with maleic anhydride (35% vinyl acetate content, 0.1% grafting rate)

[0070] 10 parts of polypropylene wax (Clariant PP6252)

[0071] 5 parts of terpene resin (T100)

[0072] Antioxidant (DSTDP) 0.4 parts

[0073] The overall grafting rate of maleic anhydride onto polypropylene was 2.5%.

[0074] The preparation method is the same as in Example 1.

[0075] Example 5

[0076] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0077] 10 parts of polypropylene resin (Lanzhou Petrochemical RP260, ethylene-propylene copolymer, melt flow rate 8.0 g / 10 min)

[0078] 30 parts of high-grafting-rate polypropylene grafted with maleic anhydride (Toyobo KE, 3.0% grafting rate, number average molecular weight 9000 g / mol)

[0079] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 1.0% grafting rate, number average molecular weight 65000 g / mol)

[0080] 5 parts of POE-grafted maleic anhydride (Nengzhiguang V series, 0.6% grafting rate)

[0081] 30 parts of polypropylene wax (Clariant 2602)

[0082] 5 parts of terpene resin (T110)

[0083] Antioxidant (B225) 0.5 parts

[0084] The overall grafting rate of maleic anhydride onto polypropylene was 2.4%.

[0085] The preparation method is the same as in Example 1.

[0086] Comparative Example 1

[0087] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0088] 10 parts of polypropylene resin (Lanzhou Petrochemical RP260, ethylene-propylene copolymer, melt flow rate 8.0 g / 10 min)

[0089] 30 parts of high-grafting-rate polypropylene grafted with maleic anhydride (Toyobo KE, 3.0% grafting rate, number average molecular weight 9000 g / mol)

[0090] 20 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 1.0% grafting rate, number average molecular weight 65000 g / mol)

[0091] 30 parts of polypropylene wax (Clariant 2602)

[0092] 5 parts of terpene resin (T110)

[0093] Antioxidant (B225) 0.5 parts

[0094] The overall grafting rate of maleic anhydride onto polypropylene was 2.5%.

[0095] The preparation method is the same as in Example 1.

[0096] Comparative Example 2

[0097] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0098] 10 parts of polypropylene resin (Lanzhou Petrochemical RP260, ethylene-propylene copolymer, melt flow rate 8.0 g / 10 min)

[0099] 50 parts of high-grafting-rate polypropylene grafted with maleic anhydride (Toyobo KE, 3.0% grafting rate, number-average molecular weight 9000 g / mol).

[0100] 5 parts of POE-grafted maleic anhydride (Nengzhiguang V series, 0.6% grafting rate)

[0101] 30 parts of polypropylene wax (Clariant 2602)

[0102] 5 parts of terpene resin (T110)

[0103] Antioxidant (B225) 0.5 parts

[0104] The overall grafting rate of maleic anhydride onto polypropylene was 2.4%.

[0105] The preparation method is the same as in Example 1.

[0106] Comparative Example 3

[0107] A hot melt adhesive for bonding polypropylene sheets comprises the following raw materials in parts by weight:

[0108] 10 parts of polypropylene resin (Lanzhou Petrochemical RP260, ethylene-propylene copolymer, melt flow rate 8.0 g / 10 min)

[0109] 50 parts of low-grafting-rate polypropylene grafted with maleic anhydride (Toyobo, 0.8% grafting rate, number average molecular weight 80000 g / mol)

[0110] 5 parts of EVA grafted with maleic anhydride (35% vinyl acetate content, 0.1% grafting rate)

[0111] Polyethylene wax (SCG Chemical LP0040p, Thailand) 30 parts

[0112] 5 parts of terpene resin (T110)

[0113] Antioxidant (1010) 0.3 parts

[0114] The overall grafting rate of maleic anhydride onto polypropylene was 2.4%.

[0115] The preparation method is the same as in Example 1.

[0116] Performance testing:

[0117] The hot melt adhesives prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to the following tests:

[0118] Peel strength test: 180° peel test, GB / T 2792-1998;

[0119] Flow performance test: 230℃, 2.16kg, GB / T 3682-2018;

[0120] The results are shown in Table 1.

[0121] Table 1 Performance tests of hot melt adhesives prepared in several experiments

[0122]

[0123] As can be seen from Table 1, the adhesive peel strength of the hot melt adhesive obtained in the embodiments of the present invention is all >10N / 15mm, which fully meets the adhesive peel strength of >7N / 15mm required for pharmaceutical packaging, and can replace the aluminum foil heat-sealing PVC adhesive.

[0124] The compatibility of the hot melt adhesives prepared in each embodiment and comparative example was tested: hot melt adhesives were etched with cyclohexane solvent and then dried to prepare hot melt adhesive samples. The morphology and structure of the hot melt adhesive samples under an electron microscope were observed to determine whether they were homogeneous and compatible. A morphology of island structure was incompatible, while a morphology of layered, sheet-like, or granular structure was compatible.

[0125] Figure 1 The image shows the SEM image of the hot melt adhesive obtained in Example 1, which shows that it has a layered structure. Figure 2 The image shows an SEM image of the hot melt adhesive obtained in Example 2, which reveals that it has a sheet-like structure. Figure 3 The image shows the SEM image of the hot melt adhesive obtained in Example 3, which shows that it has a granular structure. Figure 4 The image shows the SEM image of the hot melt adhesive obtained in Example 4, which shows that it has a layered structure. Figure 5 The image shows the SEM image of the hot melt adhesive obtained in Example 5, which shows that it has a granular structure. Figure 6 The SEM image of the hot melt adhesive obtained in Comparative Example 1 shows that it has an island structure. Figure 7 The image shows the SEM image of the hot melt adhesive obtained in Comparative Example 2, which reveals that it has a sheet-like structure. Figure 8 The SEM image of the hot melt adhesive obtained in Comparative Example 3 shows that it has an island structure.

[0126] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A hot melt adhesive for bonding polypropylene sheets, characterized in that, The raw materials include: polypropylene grafted with maleic anhydride, ethylene-octene copolymer grafted with maleic anhydride and / or ethylene-vinyl acetate copolymer grafted with maleic anhydride, polypropylene resin, polypropylene wax and / or polyethylene wax, and terpene resin; wherein the polypropylene grafted with maleic anhydride includes low grafting rate polypropylene grafted with maleic anhydride with a grafting rate of 0.8~1.2% and high grafting rate polypropylene grafted with maleic anhydride with a grafting rate of 3~5%. The polypropylene grafted maleic anhydride comprises high grafting rate polypropylene grafted maleic anhydride with a number average molecular weight of 3000-9000 g / mol and a number average molecular weight of 50000-80000 g / mol, in a mass ratio of 30:20 to 40:

20. By weight, it includes 50-60 parts of polypropylene grafted with maleic anhydride, 5-10 parts of ethylene-octene copolymer grafted with maleic anhydride and / or ethylene-vinyl acetate copolymer grafted with maleic anhydride, 10-30 parts of polypropylene resin, 10-30 parts of polypropylene wax and / or polyethylene wax, and 5-7 parts of terpene resin.

2. The polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, The polypropylene grafted with maleic anhydride is a propylene homopolymer grafted with maleic anhydride and / or an ethylene-propylene copolymer grafted with maleic anhydride.

3. The polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, The total grafting rate of the polypropylene grafted with maleic anhydride is ≥2%.

4. The polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, The maleic anhydride grafting rate of ethylene-octene copolymer grafted with maleic anhydride and / or ethylene-vinyl acetate copolymer grafted with maleic anhydride is ≤1%.

5. The polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, The polypropylene resin is homopolymer polypropylene, ethylene-propylene copolymer polypropylene, or propylene-butadiene copolymer polypropylene, and the melt flow rate ranges from 2 to 30 g / 10 min.

6. The polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, It also includes 0.1 to 0.5 parts of antioxidants.

7. The method for preparing the polypropylene sheet bonding hot melt adhesive according to claim 1, characterized in that, The preparation method of hot melt adhesive includes mixing all raw materials in a high-speed mixer to form a mixture, then adding the mixture to a twin-screw extruder for extrusion, then water-cooling the strands and cutting them into pellets in a granulator, and finally drying and packaging the pellets.

8. The preparation method according to claim 7, characterized in that, The twin-screw extruder is a parallel twin-screw extruder with a length-to-diameter ratio of 30-60:

1.

9. The preparation method according to claim 7 or 8, characterized in that, The operating temperature of a twin-screw extruder is 130-240℃.

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