Nylon material well bonded with tpu material and its preparation method

Abstract

The application discloses a reinforced nylon with good bonding performance with TPU, which is prepared from the following raw materials in mass fraction: nylon 20-60 parts, nylon elastomer 5-30 parts, glass fiber 10-60 parts, antioxidant 0-1 part, lubricant 0-1 part and branched nylon 1-5 parts. The reinforced nylon has good bonding capacity with various TPU while keeping excellent mechanical properties, and has wide application range and is not limited by the type of TPU.

Description

[0001] This invention relates to a nylon material that bonds well with TPU material and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Nylon possesses a range of excellent properties, such as good mechanical properties, abrasion resistance, chemical resistance, self-lubrication, and ease of processing. Reinforced nylon, on the other hand, offers additional advantages such as high strength, high modulus, high impact resistance, and high heat resistance. Therefore, it is widely used in the automotive, home appliance, and electronics industries. However, due to its relatively hard material, it is suitable for structural components, and its feel is often unpleasant when in direct contact with the human body. TPU refers to thermoplastic polyurethane elastomer. This type of material typically has good abrasion resistance, resilience, and a soft touch. Overmolding TPU onto reinforced nylon can provide a pleasant surface feel to the part while maintaining its strength.

[0003] The adhesion between ordinary TPU and reinforced nylon is poor. Current technologies primarily focus on modifying either the TPU or the reinforced nylon to improve their bonding performance. Patent CN111004494A discloses a thermoplastic polyurethane material capable of secondary injection bonding to nylon and its preparation method. By adding polyurethane hot melt adhesive to the TPU, the TPU imparts abrasion resistance and a soft, smooth feel, while the polyurethane hot melt adhesive provides good adhesion between the material and nylon, ultimately achieving good bonding between TPU and reinforced nylon at a relatively low temperature. However, the addition of the polyurethane hot melt adhesive somewhat affects the performance of the TPU and also limits the choice of soft adhesive. Patent CN106366649A discloses a glass fiber reinforced PA66 composite material with good adhesion to TPU. By adding high-flowability branched nylon and using low-viscosity PA66, it improves the resin's ability to encapsulate glass fibers, preventing severe fiber floating on the surface of the part, thereby enhancing the adhesion between glass fiber reinforced PA66 and TPU. The glass fiber reinforced PA66 prepared by this patent exhibits good adhesion to TPU, as well as high heat resistance and wear resistance. However, this patent only optimizes the process by improving the floating fibers on the nylon surface, without modifying the resin matrix. Furthermore, the amount of glass fiber added is limited, with a maximum of 30% wt. In addition, PA66 has a melting point of approximately 260℃, while TPU has a melting point of approximately 170℃. This significant difference in melting points makes it difficult for the molten TPU to soften the PA66 surface during secondary injection, potentially leading to poor adhesion. Summary of the Invention

[0004] To address the issues of poor adhesion between glass fiber reinforced nylon and TPU, and the limited selection of soft adhesives, this invention provides a reinforced nylon material with excellent mechanical properties and good adhesion to TPU, based on the perspective of nylon modification.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] On the one hand, the present invention provides a reinforced nylon material with strong adhesion to TPU, wherein the raw materials, by mass fraction, include:

[0007] 20-60 parts of nylon

[0008] 5-30 parts of nylon elastomer

[0009] 10-60 parts fiberglass

[0010] Antioxidant 0-1 part,

[0011] 0-1 part lubricant

[0012] Branched nylon 1-5 parts.

[0013] In this invention, there is no specific limitation on the type of nylon, but long-chain nylon is preferred. This is because long-chain nylon has a lower amide bond density and a lower melting point, which is closer to TPU. During the overmolding process, the molten TPU can better soften the surface of the nylon part and improve the adhesion effect. Specifically, the nylon is one or more of PA46, PA6, PA66, PA610, PA612, PA1010, PA1012, PA11, PA12, and PA1212. Preferably, the nylon is PA1010, PA1012, PA11, PA12, or PA1212. Most preferably, the nylon is PA12.

[0014] The nylon elastomer is a copolymerized nylon elastomer composed of hard segments and soft segments of polyamide elastomer. The hard segments of the polyamide elastomer include at least one selected from polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 1010, polyamide 1012, and polyamide 1212. The soft segments of the polyamide elastomer include at least one selected from polytetrahydrofuran ether, polyethylene glycol, polypropylene glycol, and polybutanediol. Preferably, the nylon elastomer is PA12 nylon elastomer.

[0015] The glass fiber is either unmodified or surface-modified, preferably with the surface treated with a silane coupling agent.

[0016] The antioxidant is a combination of hindered phenolic antioxidant and phosphite antioxidant, wherein the hindered phenolic antioxidant is antioxidant 1098, 1010, or 1076, preferably antioxidant 1098, and the phosphite antioxidant is antioxidant 168, 626, or 619, preferably antioxidant 168.

[0017] The lubricant is one or more of ethylene bis-stearamide, stearamide, oleamide, polyethylene wax, calcium stearate, zinc stearate, liquid paraffin, and microcrystalline wax; preferably, the lubricant is one or more of polyethylene wax, calcium stearate, and zinc stearate.

[0018] The branched nylon is selected from star-shaped branched nylons, dendritic branched nylons, or hyperbranched nylons with terminal carboxyl or amino groups, such as Hyper N10. Commercially available products can be purchased, or they can be synthesized in-house.

[0019] In one specific embodiment, the preparation method of branched nylon with terminal carboxyl groups is as follows:

[0020] (1) The amino acid monomer and the terminal ester chain branching agent were dissolved in water at a weight ratio of amino acid monomer: terminal ester chain branching agent = 100:(0.05~10) to obtain the first mixture.

[0021] (2) The first mixture is heated to carry out an amidation reaction. After the reaction is completed, the pressure is released to obtain the second mixture.

[0022] (3) Heat the mixture to a higher temperature, then vacuum it, and heat the second mixture to carry out a polycondensation reaction to obtain branched nylon.

[0023] The amino acid monomer in step (1) is selected from any one or a combination of several of aminovaleric acid, aminohexanoic acid, aminodecanoic acid, aminoundecanoic acid and aminododecanoic acid; the general formula of the terminal ester chain branching agent is X-(YZ)n, where X is a benzene ring group, melamine group, hexamethylenediamine group or ethylenediamine group; Y is a saturated aliphatic alkyl group with 2-6 carbon atoms; Z is a methyl ester group, ethyl ester group or butyl ester group, and n = 3-16.

[0024] The reaction temperature in step (2) is 100-200℃, the reaction pressure is 0.1-1MPa, and the reaction time is 1-8h.

[0025] In step (3), the reaction temperature is 200-300℃, the vacuum degree is -0.05 to -0.09 MPa, and the reaction time is 0.5-6 h.

[0026] On the other hand, the present invention provides a method for preparing a reinforced nylon material with strong adhesion to TPU, comprising the following steps: weighing raw materials other than glass fiber according to mass fraction, mixing them evenly, adding them from the main feed port of a twin-screw extruder, adding glass fiber from the side feed port, co-extruding and granulating to obtain the nylon material.

[0027] The twin-screw extruder has a processing temperature of 240-280℃ and a main screw speed of 300-600 rpm.

[0028] The present invention has the following effects:

[0029] (1) Nylon elastomer has both nylon blocks and polyether blocks, and has good compatibility with both TPU and nylon, which can improve the adhesion between the two, while having little impact on the performance of nylon materials.

[0030] (2) Since glass fiber is an inorganic filler, its adhesion to TPU is poor. Therefore, surface fiber floating affects the bond strength between reinforced nylon and TPU. Branched nylon has a large number of terminal carboxyl groups or amino groups, which can improve the compatibility between nylon resin and glass fiber, reduce surface fiber floating, and thus improve the bonding effect. In addition, branched nylon has a unique spherical molecular structure, low viscosity, and lubrication effect, which can reduce the use of wax lubricants in the material and avoid excessive wax lubricant addition affecting the bonding strength.

[0031] (3) The reinforced nylon proposed in this invention has the advantages of excellent mechanical properties and good adhesion to TPU. At the same time, it can be obtained by twin-screw co-extrusion granulation, which is simple to produce. Detailed Implementation

[0032] Raw materials and sources:

[0033] PA12, produced by Wanhua Chemical, Wanamid L1000

[0034] Fiberglass, Owens Corning, OC995

[0035] Nylon elastomers, Arkema, PEBAX

[0036] Branched nylon, commercially available or homemade, Wuhan Hyperbranched Resin Technology Co., Ltd., Hyper N10

[0037] Antioxidant, a 1:1 mixture of antioxidant 1098 and antioxidant 168, both are commercially available products.

[0038] Lubricant, lignite wax, a common commercially available product.

[0039] Example of preparation of branched nylon: (1) Aminododecanoic acid monomer and terminal ester chain branching agent were dissolved in water at a weight ratio of amino acid monomer: terminal ester chain branching agent = 100:1 to obtain a first mixture, wherein the terminal ester chain branching agent X-(YZ)n, X is a benzene ring group; Y is an ethyl group; Z is a methyl ester group, and n = 3.

[0040] (2) The first mixture was heated to 140°C and the pressure was controlled at 0.1 MPa. The terminal ester chain branching agent and the amino acid monomer underwent an amidation reaction. After 6 hours of reaction, the pressure was released to obtain the second mixture.

[0041] (3) The second mixture is heated and then vacuumed for 4 hours. The temperature is controlled at 220℃ and the vacuum degree is -0.05Mpa. The second mixture undergoes a polycondensation reaction. After 4 hours of reaction, branched nylon is obtained.

[0042] Test standards or methods:

[0043] Tensile strength and tensile modulus: obtained according to ISO 527 test;

[0044] Notched impact strength of simply supported beam: obtained according to ISO 179 test;

[0045] Adhesion: (1) Design a mold for half of the ISO527 standard tensile test strip and use reinforced nylon material for injection molding; (2) Place half of the test strip into the standard tensile test strip mold, mold temperature 70℃, keep warm for 3 minutes, inject TPU, and perform insert injection molding to obtain the tensile test strip formed by bonding nylon and TPU; (3) Place the obtained test strip in an environment of 23℃ and 50% humidity for 48 hours, and then perform a tensile test. Record the maximum force value when the test strip breaks, which is the adhesion between nylon and TPU.

[0046] Example

[0047] Preparation methods of nylon materials:

[0048] Weigh the raw materials according to the contents of Table 1, mix all raw materials except glass fiber evenly, add them from the main feed port of the twin-screw extruder, and add glass fiber from the side feed port. Blend, extrude and granulate to obtain the nylon material.

[0049] The twin-screw extruder was used at a processing temperature of 260℃ and a main screw speed of 300 rpm. The material properties were tested, and the results are shown in Table 2.

[0050] Table 1: Raw materials for examples and comparative examples

[0051]

[0052] Table 2: Test Results of Examples and Comparative Examples

[0053]

[0054] As shown in Table 2, Examples 1-8 achieved good adhesion to TPU by adding nylon elastomer and branched nylon while maintaining the material's superior mechanical properties.

[0055] As can be seen from the comparison between Example 1 and Comparative Example 1, the mechanical properties of the material are maintained well after the addition of nylon elastomer, and the adhesion to TPU is significantly improved.

[0056] As can be seen from the comparison between Example 1 and Comparative Example 2, the addition of branched nylon improves the fiber floating of the material and enhances its adhesion to TPU.

[0057] As can be seen from the comparison between Example 1 and Comparative Example 3, the present invention achieves a good compounding effect by adding nylon elastomer and branched nylon, resulting in a reinforced nylon material with superior mechanical properties, good appearance, and good adhesion to TPU.

[0058] In summary, the nylon material provided by this invention has advantages such as excellent mechanical properties, good appearance, and strong adhesion to TPU, and has a wide range of applications.

[0059] Although the invention has been described in detail above for illustrative purposes, it should be understood that such detailed description is merely for illustration, and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention, which is defined only by the claims.

Claims

1. A reinforced nylon material with strong adhesion to TPU, comprising, by mass fraction: 20-60 parts of nylon 5-30 parts of nylon elastomer 10-60 parts fiberglass Antioxidant 0-1 part, 0-1 part lubricant 1-5 parts of branched nylon; wherein the branched nylon is selected from branched nylons with terminal carboxyl groups or terminal amino groups; The nylon is one or more of PA46, PA6, PA66, PA610, PA612, PA1010, PA1012, PA11, PA12, and PA1212; The nylon elastomer is a copolymer nylon elastomer composed of polyamide elastomer hard segments and polyamide elastomer soft segments; the polyamide elastomer hard segments include at least one of polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 1010, polyamide 1012, and polyamide 1212; the polyamide elastomer soft segments include at least one of polytetrahydrofuran ether, polyethylene glycol, polypropylene glycol, and polybutanediol.

2. The reinforced nylon material as described in claim 1, characterized in that, The antioxidant is a combination of hindered phenolic antioxidants and phosphite antioxidants, wherein the hindered phenolic antioxidants are antioxidants 1098, 1010, and 1076.

3. The reinforced nylon material as described in claim 1, characterized in that, The lubricant is one or more of ethylene bis-stearamide, stearamide, oleamide, polyethylene wax, calcium stearate, zinc stearate, liquid paraffin, and microcrystalline wax.

4. The reinforced nylon material according to any one of claims 1-3, characterized in that, The branched nylon is selected from HyperN10.

5. The reinforced nylon material according to any one of claims 1-3, characterized in that, The specific preparation method of the branched nylon with terminal carboxyl groups is as follows: (1) Dissolve the amino acid monomer and the terminal ester chain branching agent in water at a weight ratio of amino acid monomer: terminal ester chain branching agent = 100: (0.05~10) to obtain the first mixture. (2) The first mixture is heated to carry out an amidation reaction. After the reaction is completed, the pressure is released to obtain the second mixture. (3) Heat the mixture to a higher temperature, then vacuum it, and heat the second mixture to carry out a polycondensation reaction to obtain branched nylon.

6. The reinforced nylon material as described in claim 5, characterized in that, The amino acid monomer in step (1) is selected from any one or a combination of several of aminovaleric acid, aminohexanoic acid, aminodecanoic acid, aminoundecanoic acid and aminododecanoic acid; the general formula of the terminal ester chain branching agent is X-(YZ)n, where X is a benzene ring group, melamine group, hexamethylenediamine group or ethylenediamine group; Y is a saturated aliphatic alkyl group with 2-6 carbon atoms; Z is a methyl ester group, ethyl ester group or butyl ester group, and n=3-16; and / or, the reaction temperature in step (2) is 100-200℃, the reaction pressure is 0.1-1MPa, and the reaction time is 1-8h; and / or, the reaction temperature in step (3) is 200-300℃, the vacuum degree is -0.05~-0.09Mpa, and the reaction time is 0.5-6h.

7. A method for preparing a reinforced nylon material with strong adhesion to TPU as described in any one of claims 1-6, comprising the following steps: weighing raw materials other than glass fiber according to mass fraction, mixing them evenly, adding them from the main feed port of a twin-screw extruder, adding glass fiber from the side feed port, co-extruding and granulating to obtain the nylon material.

8. The method as described in claim 7, characterized in that, The twin-screw extruder has a processing temperature of 240-280℃ and a main screw speed of 300-600 rpm.

Images