Coated buffer stop block and preparation method thereof

Abstract

The present invention discloses a coated buffer stop block. The coated buffer stop block includes an outer coating and a microporous elastomer inner core, the outer coating includes a main body coating and an injection port coating; the outer coating is a thermoplastic elastomer material, and the microporous elastomer inner core is a microporous elastomer foam material; the outer coating is coated on the surface of the microporous elastomer inner core, and is compressed together with it to deform to absorb impact and play a buffering role; and the outer coating is dense and smooth, which improves the wear resistance and corrosion resistance of the buffer stop block, greatly increases the product life, and copes with the stringent requirements of automobiles running in harsh environments. The present invention also discloses a preparation method for the coated buffer stop block, including blow molding to form a main body coating; injection molding to form an injection port coating; making the main body coating fit the mold and injecting microporous elastomer foam material, covering the injection port coating, closing the mold and maturing it, and then demolding to obtain the coated buffer stop block.

Description

Technical Field

[0001] The invention relates to the field of production and manufacturing of new material parts, and in particular to a buffer stop block with a coating and a preparation method thereof. Background Art

[0002] With the development of the automobile industry and the enhancement of safety awareness, the corrosion resistance of buffer stops has become increasingly important in order to cope with the situation of automobiles driving under different environmental conditions. The characteristics of the existing buffer stop foam structure have been insufficient in terms of tensile strength, wear resistance and corrosion resistance, which has affected the improvement of the overall performance of the buffer stop.

[0003] For example, the patent CN201611183138.5 provides a thermoplastic polyester elastomer composition, which can be used as a high-strength damping element that withstands dynamic fatigue, such as a buffer shock-absorbing element for vehicles such as automobiles. Thermoplastic polyester elastomer has a density of 1.2 and a tensile strength of 50Mpa. It has both the excellent elasticity of rubber and the easy processing of thermoplastics, and has high structural strength, good creep resistance, excellent resilience, impact resistance and bending fatigue resistance, wear resistance, dimensional stability, flexibility at low temperatures, and can maintain good performance at high temperatures, but there is still a lot of room for improvement in damping performance.

[0004] Another commonly used buffer stop block, polyurethane microporous elastomer, has the advantages of good elasticity, large deformation, and the ability to absorb greater impact and vibration energy. Due to the excellent damping performance of this material, it is now widely used in the production of buffer stops for automobile shock absorption.

[0005] The common production process of polyurethane microporous elastomer buffer stopper is to use a foaming machine to mix the prepolymer and polyol resin mixture in proportion, inject it into the mold, and then mature it. The polyurethane microporous elastomer produced in this way has a density of 0.6, a tensile strength of 5MPa, and a tear strength of 10kN / m. Figure 1 As shown, the inner core and the outer skin are basically the same. After a period of use, they will be affected by impurities such as water, oil, dust, and microorganisms, causing corrosion and affecting the performance of the buffer stop block.

[0006] Patent CN201010283775.6 provides a method for forming a skin-coated polyurethane core product, comprising: A. forming the skin by vacuum forming; B. placing the vacuum formed skin in a foaming mold for polyurethane foaming to form a skin-coated polyurethane core product. Patent CN201310141829.9 provides a method for producing a skin-coated foam molded product and the resulting skin-coated foam molded product, the method comprising: A. blow molding a parison into a skin; B. heating expanded polystyrene beads filled in the hollow space of the skin to form a foam layer melt-bonded to the skin. However, due to the special structure of the buffer stop block, these two coating technical methods are not suitable for preparing the coated buffer stop block. Summary of the invention

[0007] The present invention proposes a coated buffer stop block, the main purpose of which is to overcome the defects of poor corrosion resistance and short service life of polyurethane buffer stop blocks for automobiles; at the same time, a preparation method of a coated buffer stop block is proposed to overcome the deficiencies in the prior art for making the coated buffer stop block.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a coated buffer stop block, characterized in that it includes an outer coating and a microporous elastomer inner core; the microporous elastomer inner core is a hollow rotating body structure, and the outer circumferential surface and the inner circumferential surface of the microporous elastomer inner core are both corrugated; the outer coating is coated on the surface of the microporous elastomer inner core; the microporous elastomer inner core is a microporous foam material, and the outer coating is a thermoplastic elastomer material.

[0009] Specifically, the outer layer coating includes a main body coating and an injection port coating.

[0010] Specifically, the main body coating and the injection port coating are made of thermoplastic elastomer materials with different chemical compositions.

[0011] Specifically, the density of the microporous foam material is 0.3 to 0.9 g / cm 3 between.

[0012] Specifically, the pore size of the microporous foam material is 0.1-10 μm.

[0013] As a preferred technical solution of the present invention, the microporous foam material is a polyurethane material.

[0014] As a preferred technical solution of the present invention, the microporous foam material is a rubber material.

[0015] As a preferred technical solution of the present invention, the thermoplastic elastomer material is TPU.

[0016] The present invention also provides a method for preparing the coated buffer stop block, comprising the following steps:

[0017] Step A: using injection molding process to make the injection port coating;

[0018] Step B. Extruding or injection molding to obtain a main body coated tubular parison;

[0019] Step C. placing the tubular parison in a heated and softened state into a mold for inflating so that it clings to the inner wall of the mold to form a hollow product;

[0020] Step D: after cooling and shaping, inject the microporous foam material into the hollow inner cavity of the main body coating, cover the injection port with the coating, and close the mold;

[0021] Step E: The microporous foam material is cross-linked, cured and foamed to form a microporous elastic body core, and the film-coated buffer stop block is obtained by demoulding.

[0022] Specifically, the mold includes a cover mold, two side molds and a core mold.

[0023] Specifically, during the process of extruding or injection molding the main body coated tubular preform in step B, the main body coated tubular preform is heated, and can be directly placed in a mold in a heated and softened state for the inflation operation in step C; or after the main body coated tubular preform is cooled and stabilized, it can be heated to a softened state and then placed in a mold for the inflation operation in step C. Therefore, the two processes of making the tubular preform in step B and the inflation in step C can be performed separately and independently in time.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The coated buffer stop block described in the present invention comprises an outer coating and a microporous elastomer inner core. The outer coating is dense and smooth, and has the advantages of oil resistance, water resistance, mildew resistance, and high temperature resistance. It reduces the degree of adsorption of dirt, improves the wear resistance and corrosion resistance of the buffer stop block, greatly increases the product life, and can better meet the stringent requirements of automobile operation in harsh environments. At the same time, a preparation method of a coated buffer stop block is proposed, which overcomes the deficiency of the coated buffer stop block for making the hollow rotating body structure in the prior art, and the microporous foam material and the thermoplastic elastomer material for making the outer coating and the microporous elastomer inner core have good processing performance and are easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A cross-sectional schematic diagram of a buffer stop block in the prior art;

[0027] Figure 2 A schematic cross-sectional view of a coated buffer stop block according to an embodiment of the present invention;

[0028] Figure 3A three-dimensional diagram of a coated buffer stop block according to an embodiment of the present invention;

[0029] Figure 4 A three-dimensional diagram of a film-coated buffer stop block and a manufacturing mold according to an embodiment of the present invention;

[0030] Figure 5 A cross-sectional schematic diagram of a coated buffer stop block and a manufacturing mold according to an embodiment of the present invention;

[0031] Figure 6 A schematic cross-sectional view of a hollow parison formed by coating the main body according to an embodiment of the present invention;

[0032] Figure 7 A schematic cross-sectional view of an outer coating according to an embodiment of the present invention;

[0033] Description of symbols in the accompanying drawings:

[0034] 1 Top

[0035] 2 Bottom

[0036] 11. Filling port lamination

[0037] 12 Polyurethane microporous elastomer inner core

[0038] 13 Main body coating

[0039] 21 Cover mold

[0040] 22 Side mould

[0041] 23 Core mold

[0042] 24 Coated buffer stop block DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The embodiment of the present invention provides a film-coated buffer stop block, such as Figure 2 , 3 As shown, it includes an outer layer coating and a microporous elastic body core, and the density of the polyurethane microporous elastic material is 0.3-0.9 g / cm 3The pore size is between 0.1 and 10 μm; in this embodiment, the microporous elastomer inner core is a polyurethane microporous elastomer inner core 12, which is compressed to deformation to absorb impact and play a buffering role; the polyurethane microporous elastomer inner core 12 is a hollow rotating body structure, and its outer and inner surfaces are both corrugated. In this embodiment, there are three corrugations on the outer surface and five corrugations on the inner surface, but in other embodiments, it is not limited to this and can be changed for different design purposes, and the size of the diameter of the corrugations, whether they are the same, and whether the distribution density of the corrugations is uniform can all be changed for different design purposes; the top 1 of the polyurethane microporous elastomer inner core 12 is a nearly circular arch with a central depression, and the bottom 2 is a smooth cross-section.

[0045] The outer coating is coated on the surface of the polyurethane microporous elastomer inner core 12, and is compressed together with the polyurethane microporous elastomer inner core 12 to deform to absorb impact and play a buffering role; the outer coating includes a main coating 13 and an injection port coating 11, the injection port coating 11 covers the small opening on the bottom outer surface of the polyurethane microporous elastomer inner core 12, and the main coating 13 covers the rest of the surface of the polyurethane microporous elastomer inner core 12; in this embodiment, the outer coating is TPU (thermoplastic polyurethane elastomer material). TPU, as an elastomer, is a type of polymer material between rubber and plastic, with a density of about 1.2 g / cm 3 , it has good elasticity, a wide range of hardness, excellent wear resistance and tear resistance, and as the hardness increases, the product can still maintain good elasticity and wear resistance; and TPU also has the properties of oil resistance, water resistance, mildew resistance, and high temperature resistance, and has good processing performance, and can be processed using common thermoplastic material processing methods. The main body coating 13 and the injection port coating 11 of the outer layer coating can also be thermoplastic polymer elastomer materials with different chemical compositions.

[0046] Since the -NCO group in the polyurethane molecular chain can react with a variety of functional groups containing active hydrogen to form an interfacial chemical bond, it has extremely strong adhesion to a variety of materials and can bond porous materials such as foam plastics, ceramics, wood, fabrics, etc. It can also bond a variety of metals, inorganic materials, plastics, rubbers, leathers, etc. The polyurethane microporous elastomer inner core 12 and the TPU outer layer film are bonded, specifically through: A. chemical bond force, B. intermolecular force, and C. mechanical force to form a very high bonding strength.

[0047] The embodiment of the present invention also provides a method for preparing the coated buffer stop block, wherein the mold used in the preparation method is as follows: Figure 4 , 5As shown, it includes a cover mold 21, two side molds 22 and a core mold 23; the core mold 23 is a slender cylinder, the base of the cylinder is cylindrical, used for assembly and fixation of the mold, and the upper part of the cylinder is distributed with corrugations, which are used to form the corrugations on the inner circumference of the inner core 12 of the polyurethane microporous elastomer; the cover mold 21 is in the shape of two circular cakes with different diameters connected up and down, which is used to close the mold; the two side molds 22 are symmetrical, and the side connected to each other has corrugated grooves, which are used to form the corrugations on the outer circumference of the inner core 12 of the polyurethane microporous elastomer, and the bottom has a cylindrical groove for splicing and assembling with the base of the core mold 23, and the top has a groove for splicing and assembling with the cover mold 21. The grooves and corrugations of the side molds 22 and the core mold 23 can also be designed to have different shapes and densities according to product requirements.

[0048] The specific steps of the method for preparing the coated buffer stop block are as follows:

[0049] Step A: using injection molding process to make the injection port coating;

[0050] Step B. Extruding or injection molding to obtain a main body coated tubular parison;

[0051] Step C: placing the tubular preform in a heated and softened state into a mold for inflation so that the preform adheres closely to the inner wall of the mold to form a hollow product (such as Figure 6 shown);

[0052] Step D: After cooling and shaping, inject the microporous foam material into the hollow inner cavity of the main body film, and cover the injection port film (such as Figure 7 As shown), close the mold;

[0053] Step E: The microporous foam material is cross-linked, cured and foamed to form a microporous elastic body core, and the film-coated buffer stop block is obtained by demoulding.

[0054] During the process of extruding or injection molding the main body coated tubular preform in step B, the main body coated tubular preform is heated, and can be directly placed in a mold in a heated and softened state for the inflation operation in step C; or after the main body coated tubular preform is cooled and stabilized, it can be heated to a softened state and then placed in a mold for the inflation operation in step C. Therefore, the two processes of making the tubular preform in step B and the inflation in step C can be performed separately and independently in time.

[0055] In summary, the above embodiments are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a coated buffer stop block, characterized in that: The coated buffer stop block comprises an outer coating and a microporous elastomer inner core; the microporous elastomer inner core is a hollow rotating body structure, and the outer circumference and inner circumference of the microporous elastomer inner core are both corrugated; the outer coating is coated on the surface of the microporous elastomer inner core, and the outer coating comprises a main body coating and an injection port coating; the microporous elastomer inner core is a microporous foam material, and the outer coating is a thermoplastic elastomer material; The method for preparing the coated buffer stop block comprises the following steps: Step A. Using injection molding process to make the injection port coating; Step B. Extruding or injection molding to obtain a main body coated tubular parison; Step C. placing the tubular parison in a heated and softened state into a mold for inflating so that it closely adheres to the inner wall of the mold to form a hollow product; Step D. After cooling and shaping, inject the microporous foam material into the hollow inner cavity of the main body coating, cover the injection port coating, and close the mold; Step E: The microporous foam material is cross-linked, cured and foamed to form a microporous elastic body core, and the film-coated buffer stop block is obtained by demoulding.

2. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The injection port coating is located on both sides of the bottom of the coating buffer stop block close to the hollow position.

3. The method for preparing the coated buffer stopper according to claim 2, characterized in that: The main body coating and the injection port coating are made of thermoplastic elastomer materials with different chemical compositions.

4. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The density of the microporous foam material is 0.3-0.9 g / cm 3 between.

5. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The pore size of the microporous foam material is 0.1-10 μm.

6. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The microporous foam material is a polyurethane material.

7. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The microporous foam material is a rubber material.

8. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The thermoplastic elastomer material is TPU.

9. The method for preparing the coated buffer stopper according to claim 1, characterized in that: The mold comprises a cover mold, two side molds and a core mold.

Images