Spring piece for chassis of ergonomic chair and preparation process of spring piece

Abstract

A preparation process of a spring piece for an ergonomic chair chassis relates to the technical field of spring piece preparation, and comprises the following steps: S1, mixing resin and a curing agent, and vacuumizing to discharge bubbles to prepare matrix resin; s2, uniformly pouring the matrix resin prepared in the step S1 on release paper, fully impregnating the glass fiber material and the matrix resin on the release paper, and rolling to prepare a unidirectional prepreg; s3, cutting the one-way prepreg prepared in the S2 according to the specification of a single spring piece unit, then sequentially laying a plurality of layers of spring piece units, putting the spring piece units into a die for die forming, and taking out the spring piece after cooling to obtain a spring piece; the spring piece prepared by the preparation process can ensure good load, and also has good toughness, fatigue resistance and bending strength.

Description

Technical Field

[0001] The invention relates to the technical field of spring sheet preparation, and in particular to a spring sheet used for an ergonomic chair chassis and a preparation process thereof. Background Art

[0002] Due to the rise of ergonomics and the emphasis on health issues, the demand for ergonomic chairs has surged, driving the rapid growth of the market. At present, most ergonomic chairs on the market use self-loaded rod-controlled chassis, single spring rod-controlled chassis and double spring wire-controlled chassis. This chassis has uneven elasticity and a short lifespan, so ergonomic chairs with double glass fiber spring leaf chassis have appeared. However, due to certain technical barriers, only a very small number of manufacturers have adopted double glass fiber spring leaf chassis. This chassis solves the problem of uneven reclining resistance and will not break suddenly. However, most of the spring leaves in the only double glass fiber spring leaf chassis are made by prepreg molding and then cutting. This method is not easy to control the accuracy of the size and will cause certain damage to the fiber, which will affect the anti-fatigue performance of the spring leaf. In addition, the current glass fiber spring leaf is slightly lacking in toughness, resulting in a relatively small reclining angle and a narrow range of adaptation, which cannot reach the most comfortable angle for the human body. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a spring sheet for an ergonomic chair chassis and a preparation process thereof, which solves the problems of poor fatigue resistance and limited deformation of the spring sheet in the prior art.

[0004] A preparation process of a spring sheet for an ergonomic chair chassis comprises the following steps:

[0005] S1. The resin and curing agent are mixed and then vacuumed to remove bubbles to obtain a base resin;

[0006] S2. The matrix resin prepared in S1 is evenly poured onto the release paper, and then the glass fiber material and the matrix resin on the release paper are fully impregnated and rolled up to obtain a unidirectional prepreg;

[0007] S3. The unidirectional prepreg obtained in S2 is cut according to the specifications of a single spring sheet unit, and then the spring sheet units are laid in several layers in sequence, put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0008] Preferably, in step S1, the mass ratio of the resin to the curing agent is 100:107.

[0009] Preferably, in step S1, a mold release agent and carbon black accounting for 2% of the total mass of the base resin are first added to the base resin, and then the base resin and the curing agent are mixed.

[0010] Preferably, in step S1, the resin is epoxy resin.

[0011] Preferably, in step S2, in the prepared unidirectional prepreg, the content of glass fiber material is 70-80wt%, and the content of matrix resin is 20%-30wt%.

[0012] Preferably, in step S2, the glass fiber material is low modulus high strength glass fiber, with a tensile strength of 3000 MPa, an elastic modulus of 80 GPa, and an elongation at break of 7%.

[0013] Preferably, the linear density of the low modulus and high strength glass fiber is 1200tex, 2400tex or 3800tex.

[0014] Preferably, in step S3, the number of layers laid is 4-6.

[0015] The present invention also provides a spring sheet for an ergonomic chair chassis, which is prepared by the preparation process described in any one of claims 1 to 8.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention selects low modulus and high strength glass fiber. Compared with the high modulus and high strength glass fiber currently used in the existing spring sheets, the low modulus glass fiber has a lower modulus and a higher elongation at break while having a higher strength, so that it can produce a larger deformation when subjected to the same load. The chassis of the ergonomic chair needs to repeatedly withstand the force of leaning back, which requires the spring sheet to have sufficient toughness to achieve a larger and more comfortable reclining angle and a larger elastic stroke.

[0018] 2. Moreover, the spring sheet prepared by cutting the prepared prepreg into the required size of a single piece and then molding it has a more precise product size and can protect the fiber from damage. The surface quality of the product is also higher, and there will be no white silk or unevenness. It also guarantees the fatigue resistance of the spring sheet to a certain extent, so that the surface is basically intact after 300,000 fatigue tests under a downward pressure of 95mm. DETAILED DESCRIPTION

[0019] In order to make the technical means, creative features, objectives and functions of the present invention clearer and easier to understand, the present invention is further described below in conjunction with specific embodiments:

[0020] Example 1

[0021] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0022] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 2400tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 75wt%, and the content of the matrix resin is 25wt%.

[0023] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 6 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0024] Example 2

[0025] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0026] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 2400tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 75wt%, and the content of the matrix resin is 25wt%.

[0027] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 5 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0028] Example 3

[0029] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0030] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 2400tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 75wt%, and the content of the matrix resin is 25wt%.

[0031] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 4 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0032] Example 4

[0033] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0034] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 2400tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 80wt%, and the content of the matrix resin is 20wt%.

[0035] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 6 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0036] Example 5

[0037] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0038] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 2400tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 70wt%, and the content of the matrix resin is 30wt%.

[0039] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 6 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0040] Example 6

[0041] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0042] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 1200tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 75wt%, and the content of the matrix resin is 25wt%.

[0043] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 6 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0044] Example 7

[0045] S1. The epoxy resin and the curing agent are weighed in a mass ratio of 100:107, and the weighed epoxy resin, 2% of the total mass of the epoxy resin, and carbon black are added to the container, and then the curing agent is added and mixed and stirred thoroughly, and then the bubbles are removed by vacuum to obtain a base resin;

[0046] S2. Pour the matrix resin prepared in S1 evenly onto the release paper, and then fully impregnate the low modulus high strength glass fiber with a linear density of 3800tex and the matrix resin on the release paper, and then roll it up to obtain a unidirectional prepreg, wherein the content of the low modulus high strength glass fiber is 75wt%, and the content of the matrix resin is 25wt%.

[0047] S3. The unidirectional prepreg prepared in S2 is cut according to the specifications of a single spring sheet unit, and then 6 layers of spring sheet units are laid, and then put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

[0048] Comparative Example 1

[0049] Compared with Example 1, high modulus and high strength glass fiber with a linear density of 2400tex is used, and the remaining steps are the same.

[0050] Comparative Example 2

[0051] Compared with Example 1, high modulus and high strength glass fiber with a linear density of 1200tex is used, and the remaining steps are the same.

[0052] Comparative Example 3

[0053] Compared with Example 1, high modulus and high strength glass fiber with a linear density of 3800tex is used, and the remaining steps are the same.

[0054] Among them, the tensile strength of the high modulus and high strength glass fiber in the above comparative examples 1-3 is 3200 MPa, the elastic modulus is 96 GPa, and the elongation at break is 4%.

[0055] The properties of the spring sheets prepared in Examples 1-7 and Comparative Examples 1-3 were tested, and the test results are shown in the following table:

[0056]

[0057] In Examples 1-3, due to the different numbers of laying layers, the thickness of the prepared spring sheets is different, which causes the bending strength thereof to change. From the data of Examples 1-3 in the above table, it can be seen that the thickness of the spring sheet is proportional to the bending strength. Therefore, the spring sheet prepared by laying 6 layers of spring sheet units has the best fatigue resistance and the best toughness. Too few laying layers will result in insufficient bending strength of the spring sheet and easy breakage. Too many laying layers will result in excessive thickness of the spring sheet, affecting its use.

[0058] In Example 1 and Examples 4-5, the different contents of low modulus high strength glass fiber and matrix resin have an impact on the performance of the prepared spring leaf. It can be seen from the above table that when the content of low modulus high strength glass fiber is 75wt% and the content of matrix resin is 25wt%, the spring leaf has the largest bending strength, the best fatigue resistance and the best toughness.

[0059] In Example 1 and Examples 6-7, low modulus high strength glass fibers with different linear densities also have a certain influence on the performance of the spring leaf. It can be seen from the above table that the spring leaf made of low modulus high strength glass fibers with a linear density of 1200 tex or 2400 tex has good bending strength, optimal fatigue resistance and good toughness. However, the smaller the linear density of the low modulus high strength glass fiber, the greater the difficulty of processing, which will increase the production cost.

[0060] It can also be seen from the above table that, compared with Comparative Examples 1-3, after replacing the high modulus and high strength glass fiber in Example 1, no matter how much linear density of the high modulus and high strength glass fiber is used, its bending strength, fatigue resistance and toughness are not as good as those of the low modulus and high strength glass fiber; and when compared between Comparative Examples 1-3, the performance of the spring sheet prepared by the high modulus and high strength glass fiber with a linear density of 1200tex or 2400tex is still better.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A process for preparing a spring sheet for an ergonomic chair chassis, characterized in that: The following steps are involved: S1. The resin and curing agent are mixed and then vacuumed to remove bubbles to obtain a base resin; S2. The matrix resin prepared in S1 is evenly poured onto the release paper, and then the glass fiber material and the matrix resin on the release paper are fully impregnated and rolled up to obtain a unidirectional prepreg; S3. The unidirectional prepreg obtained in S2 is cut according to the specifications of a single spring sheet unit, and then the spring sheet units are laid in several layers in sequence, put into a mold for compression molding, and taken out after cooling to obtain a spring sheet.

2. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S1, the mass ratio of the resin to the curing agent is 100:

107.

3. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S1, it is necessary to first add 2% of the total mass of the release agent and carbon black into the base resin, and then mix the base resin with the curing agent.

4. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S1, the resin is epoxy resin.

5. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S2, in the prepared unidirectional prepreg, the content of glass fiber material is 70-80wt%, and the content of matrix resin is 20%-30wt%.

6. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S2, the glass fiber material is low modulus high strength glass fiber, with a tensile strength of 3000 MPa, an elastic modulus of 80 GPa, and an elongation at break of 7%.

7. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 6, characterized in that: The linear density of the low modulus high strength glass fiber is 1200tex, 2400tex or 3800tex.

8. The process for preparing a spring sheet for an ergonomic chair chassis according to claim 1, characterized in that: In step S3, the number of layers laid is 4-6.

9. A spring sheet for an ergonomic chair chassis, characterized in that: It is prepared by the preparation process described in any one of claims 1 to 8.

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