A modified polybutene resin, preparation method and application

Abstract

The present invention discloses a modified polybutene resin, a preparation method and an application thereof. The modified polybutene resin is prepared from the following components by mass percentage: 89-99.8% of a polymer, 0.1-5% of a polar monomer, and 0.1-1% of a peroxide. The polymer is an isotactic homopolymer of poly-1-butene or a block copolymer of poly-1-butene and a second monomer. By adding a peroxide initiator, the present invention grafts the polar monomer onto the polybutene resin and simultaneously improves the fluidity of the polybutene resin, thereby obtaining better toughness and adhesion than the existing polypropylene powder.

Description

Technical Field

[0001] The present invention relates to thermoplastic powder coatings, in particular to a polybutene powder coating for dip coating used in bowl basket encapsulation and a preparation method thereof. Background Art

[0002] A bowl basket is a rack used in a dishwasher to hold dishes. There are mainly two types: stainless steel or encapsulated steel. Compared with stainless steel bowl baskets, bowl baskets made of encapsulated steel are cheaper in cost, and the surface coating can buffer impacts and reduce the probability of dishes being broken by impact. The encapsulation on the surface of the bowl basket is usually achieved by fluidized bed dip coating.

[0003] The plastic powders used for bowl basket dip coating are usually divided into two categories: low melting point polyamides and polypropylenes. Polypropylene has received wide attention because of its relatively low price and better water resistance, salt resistance, and detergent corrosion resistance in the use environment.

[0004] When polypropylene is used as a bowl basket coating, it has a high hardness and good gloss, but the fusion between polypropylene powders is poor. Usually, during the bending process of metal parts, cracking occurs. Using common PP toughening methods, such as adding polyethylene-based resins or elastomers for toughening, it cannot improve its bending performance, but instead loses other properties such as surface hardness, scratch resistance, and adhesion. If the adhesion between the coating and the steel surface is reduced, better bending performance can be obtained, but the adhesion is poor, and there is also a risk of cracking during long-term use. If polypropylene powder is prepared by an elastomer toughening method, the toughness is improved to a certain extent, but the surface hardness and scratch resistance are sacrificed to a certain extent. In addition, the fluidity difference between polypropylene and the elastomer also needs to be carefully adjusted, otherwise, it is more likely to have leveling problems. Summary of the Invention

[0005] The present invention aims to improve the bending toughness of polypropylene coatings while maintaining their scratch resistance and adhesion.

[0006] The specific technical solution of the present invention is as follows:

[0007] The first object of the present invention is to provide a modified polybutene resin, which is prepared from the following components by mass percentage:

[0008] Polymer 89 - 99.8%,

[0009] Polar monomer 0.1 - 5%,

[0010] Peroxide 0.1 - 1%.

[0011] The polymer is an isotactic homopolymer of poly-1-butene or a block copolymer of poly-1-butene and a second monomer.

[0012] That is, the modified polybutene resin grafts 0.1-5% of polar monomers onto the main chain of the polymer through chemical reactions. The polymer is isotactic homopolymer of poly-1-butene or block copolymer with less than 5% of ethylene or propylene monomers added.

[0013] In a further embodiment, the second monomer is ethylene and / or propylene, and it accounts for 5% of the mass of the polymer.

[0014] In a further embodiment, the melting point of the modified polybutene resin is not lower than 120 °C, the melt index is 30-150 g / 10 min at 190 °C / 2.16 kg, the isotacticity is >90%, and the hardness is >55D.

[0015] In a further embodiment, the melt index of the isotactic homopolymer of poly-1-butene is 4-10 g / 10 min at 230 °C / 2.16 kg.

[0016] In a further embodiment, the polar monomer is maleic anhydride, maleic acid, acrylic acid and its esters, methacrylic acid and its esters, glycidyl methacrylate or vinyl silane coupling agent.

[0017] In a further embodiment, the peroxide is dicumyl peroxide, bis(tert-butylperoxy)diisopropylbenzene or di-tert-butyl peroxide.

[0018] Another object of the present invention is to provide a preparation method of the above-mentioned modified polybutene resin, which comprises the following steps:

[0019] Adding the polymer, peroxide and polar monomer into a twin-screw extruder, reacting and extruding and pelletizing at 160-220 °C to obtain the modified polybutene resin.

[0020] The third object of the present invention is to provide an application of the above-mentioned modified polybutene resin, which is used as a surface coating material for the dishwasher basket. The adhesion between the coating material and the dishwasher basket is greater than 10 N / cm, preferably 15-20 N / cm.

[0021] In a further embodiment, the surface coating material for the dishwasher basket further comprises an anti-caking agent and color powder, and the addition amount of the modified polybutene resin is 94-99.5%.

[0022] The polybutene resin is similar in structure to the polypropylene resin. There are also isotactic and atactic polybutenes, and it can form random or block copolymers with other monomers such as ethylene. The polybutene resin is superior to the toughened modified polypropylene resin in terms of hardness, toughness, leveling property, adhesion and edge coverage, while the water resistance and aging resistance are comparable to those of the polypropylene resin. It can completely replace the polypropylene resin for the surface rubber coating of the dishwasher basket.

[0023] In addition, although polybutene has a higher adhesion to metals than polypropylene, it is itself a non-polar resin, and its bonding force with metals is still weak. Therefore, polar monomers need to be grafted onto its main chain. In the present invention, these monomers are introduced through reactive extrusion granulation in the presence of peroxides, thereby obtaining a modified polybutene resin.

[0024] The beneficial effects of the present invention are as follows. Compared with the toughened PP material used as the surface coating material for the bowl basket, it has better toughness and surface hardness, especially in terms of aging resistance, crack resistance, and adhesion, which are far higher than those of PP materials. Compared with long-chain nylon materials, it has a lower price and better water resistance.

[0025] In this application, an isotactic homopolymer of poly-1-butene resin or a block copolymer of poly-1-butene and a second monomer is selected. During the extrusion process, peroxides and polar monomers are added, enabling the polar monomers to be grafted onto the main chain of polybutene, thereby making it adhesive to metals. The addition of peroxides will increase the melt index of polybutene, making it easy to level on the surface of the bowl basket.

[0026] This application selects poly-1-butene as the matrix, and its advantages compared with polypropylene are good aging resistance, crack resistance, and adhesion.

[0027] In the present invention, by adding a peroxide initiator, polar monomers are grafted onto the poly-1-butene resin, and at the same time, the fluidity of the polybutene resin is increased, thereby obtaining better toughness and adhesion than the existing polypropylene powder. Specific Embodiments

[0028] The following specific embodiments are used to further explain and illustrate the present invention, so that those skilled in the art can better understand the present invention and be able to implement it. However, the specific embodiments given are not intended to limit the present invention.

[0029] 1. The raw materials and suppliers involved in the following examples or comparative examples are as follows. It should be noted that raw materials produced by other raw materials or manufacturers are also applicable to the present invention.

[0030] Modified polybutene A1: Self-made, melt index 30 g / 10 min (190 °C / 2.16 kg), maleic anhydride grafting rate 0.1%. 99.6% of poly-1-butene resin with a melt index of 4 g / 10 min (230 °C / 2.16 kg), 0.2% of ditert-butyl peroxide diisopropylbenzene, and 0.2% of maleic anhydride are reacted and extruded in a twin-screw extruder at 190 °C to obtain the target polymer.

[0031] Modified polybutene A2: Self-made, melt index 60 g / 10 min (190 °C / 2.16 kg), maleic anhydride grafting rate 0.2%. 99.3% of poly-1-butene resin with a melt index of 10 g / 10 min, 0.4% of diisopropylbenzene peroxide, and 0.3% of maleic anhydride were reacted and extruded in a twin-screw extruder at 190 °C to obtain the target polymer.

[0032] Modified polybutene A3: Its melt index is 150 g / 10 min (190 °C / 2.16 kg), and the content of methacrylic acid is 5%. 94.2% of the poly-1-butene and ethylene block copolymer with a melt index of 10 g / 10 min, 0.8% of di-tert-butyl peroxide, and 5% of methacrylic acid were reacted and extruded in a twin-screw extruder at 190 °C to obtain the target polymer.

[0033] Polybutene B: 0300M, LyondellBasell, Netherlands

[0034] Polypropylene: L670M, Lotte, South Korea

[0035] Toughening agent: 3092PM, EPDM, Mitsui

[0036] Compatibilizer: CA100, SK chemical, South Korea

[0037] Color powder: Carbon black, titanium dioxide and other color powders

[0038] 2. The standards for the tests involved in the examples are as follows:

[0039] Mechanical properties: GB / T 1040 - 2018, Type I specimen

[0040] Hardness: GB / T 2411 - 2008

[0041] Melt index: GB / T 3682.1 - 2018, 230 °C, 2.16 kg

[0042] Bending resistance: For a metal rack coated with a 350 - micron coating, at a distance of 75 mm from the solder joint, press the rack at a 45 - degree angle and observe whether the coating at the solder joint cracks;

[0043] Adhesion: Scratch the coating on the metal surface, and then use a tensile machine to pull it along the 180° direction to measure the peel force.

[0044] 3. Sample preparation and dip coating

[0045] After premixing the materials in Table 1, the coated material is obtained by twin-screw extrusion granulation. After drying at 100 degrees Celsius, it is cooled to below -100 degrees Celsius with liquid nitrogen, and the coated material is crushed into particles with a D50 diameter of less than 150 microns using mechanical crushing equipment. After the powder temperature returns to room temperature, a small amount of anti-caking agent is added and mixed evenly. Finally, the mixed powder is put into a fluidized bed, the workpiece is heated to above 300 degrees, immersed in the fluidized bed for surface coating, the temperature is allowed to rise back to above 160 degrees, and then taken out and cooled for relevant performance testing, as shown in Table 2 specifically.

[0046] Table 1:

[0047]

[0048] Table 2:

[0049]

[0050]

[0051] By comparing Comparative Example 1 and Example 1, it can be seen that for the modified polybutene resin, the hardness and mechanical properties are basically the same as those of the unmodified polybutene, but the adhesion is significantly improved. And due to a higher melt index, the leveling property after dip coating is better.

[0052] By comparing Comparative Example 2 and Example 1, it can be seen that by adding maleic anhydride grafted polypropylene to the unmodified polybutene resin, the adhesion can be improved to a certain extent, but the effect is still inferior to that of the graft-modified polybutene.

[0053] By comparing Comparative Example 3 and Example 1, it can be seen that in Comparative Example 3, random polypropylene is used as the base material and toughened with POE. Even though the strength and hardness of the material are better than those of Example 1, the coating still cracks during bending, and the adhesion also decreases compared to Comparative Example 2.

[0054] By comparing Example 1 and Example 2, it can be seen that adding maleic anhydride grafted polypropylene can further improve the adhesion and strength of the coating, and has no effect on other properties.

[0055] By comparing Example 1, Example 3, and Example 4, it can be seen that as the content of the grafted material increases, the adhesion of the coating will further increase, while having little effect on the performance of the coating itself.

[0056] Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. Application of a modified polybutene resin, characterized in that: it is used as a surface coating material for a dishwasher basket, and its adhesion is greater than 10 N / cm; the modified polybutene resin is prepared from the following components by mass percentage: 94.2 - 99.8% of polymer, 0.1 - 5% of polar monomer, 0.1 - 1% of peroxide; the polymer is isotactic poly-1-butene homopolymer or a block copolymer of poly-1-butene and a second monomer.

2. The application of the modified polybutene resin according to claim 1, characterized in that: the second monomer is ethylene and / or propylene, and it accounts for 5% of the mass of the polymer.

3. The application of the modified polybutene resin according to claim 1, characterized in that: The melting point of the modified polybutene resin is not lower than 120 o °C, and the melt index is 30 - 150 g / 10 min at 190 o °C / 2.16 kg, the isotacticity > 90%, and the hardness > 55D.

4. The application of the modified polybutene resin according to claim 1, characterized in that: The melt index of the poly-1-butene isotactic homopolymer described is 4-10 g / 10 min at 230 o °C / 2.16 kg.

5. The application of the modified polybutene resin according to claim 1, characterized in that: the polar monomer is maleic anhydride, maleic acid, acrylic acid and its esters, methacrylic acid and its esters, glycidyl methacrylate or vinyl silane coupling agent.

6. The application of the modified polybutene resin according to claim 1, characterized in that: the peroxide is dicumyl peroxide, bis(tert-butylperoxy)diisopropylbenzene or di-tert-butyl peroxide.

7. An application according to any one of claims 1 - 6, characterized in that: the preparation method of the modified polybutene resin includes the following steps: Add the polymer, peroxide and polar monomer into a twin-screw extruder, and react and extrude into pellets at 160 - 220 o °C to obtain the modified polybutene resin.

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