Polyurethane resin composition, steering wheel, and method for manufacturing polyurethane resin composition

Abstract

To enhance hardness of a polyurethane resin composition even though polyol whose basic skeleton is an ethylene oxide chain is mainly used as a polyol component, and also reduce carbon dioxide discharge because the polyurethane resin composition is composed of lignin that is a biomaterial.SOLUTION: A polyurethane resin composition is formed from a reaction between an isocyanate component, a polyol component, and a filler. The polyol component mainly includes polyol whose basic skeleton is an ethylene oxide chain. The filler is a modified lignin that is modified by combining polyethylene glycol.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a polyurethane resin composition, a steering wheel, and a method for producing a polyurethane resin composition. [Background technology]

[0002] Patent Document 1 discloses a steering wheel for an automobile. The steering wheel disclosed in Patent Document 1 includes a core metal having a ring portion and a polyurethane covering material that covers the ring portion. The polyurethane is formed by reacting polyisocyanate and polyol.

[0003] Conventionally, in polyurethane resin compositions constituting steering wheel covering materials, polypropylene glycol (PPG) has been used as the polyol because it has a suitable hardness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-77379 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for adding biomass materials derived from living organisms to steering wheel covering materials in order to reduce the use of fossil fuels and, in turn, reduce emissions of carbon dioxide, a greenhouse gas.

[0006] However, it is difficult to add biomass materials to PPG. One solution to this problem is to use polyethylene glycol (PEG) as the polyol component, but in this case, the hardness of the covering material is lower than when PPG is used as the polyol component, making it difficult to use as a covering material for steering wheels.

[0007] It should be noted that these problems are not limited to polyurethane resin compositions for use as steering wheel covering materials, but are also found in other polyurethane resin compositions. [Means for solving the problem]

[0008] Various embodiments of a polyurethane resin composition, a steering wheel, and a method for producing a polyurethane resin composition that solves the above problems will be described below. [Aspect 1] A polyurethane resin composition formed by reacting an isocyanate component, a polyol component, and a filler, The polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, The filler is a modified lignin modified by bonding polyethylene glycol. Polyurethane resin composition.

[0009] In a polyurethane resin composition, when the polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, the hardness becomes lower than when the polyol component mainly contains a polyol having a propylene oxide chain as a basic skeleton.

[0010] According to the above configuration, the modified lignin filler is modified by bonding polyethylene glycol to the lignin. Furthermore, the lignin constituting the modified lignin has a high hardness due to the presence of a benzene ring. This increases the hardness of the polyurethane resin composition. This is thought to be because, when the polyurethane resin composition is formed, the OH groups of the modified lignin react to bond polyurethane chains together, limiting the degree of freedom of deformation of the polyurethane chains.

[0011] Therefore, the hardness of the polyurethane resin composition can be increased even though the polyol component mainly uses a polyol having an ethylene oxide chain as the basic skeleton. Furthermore, because the polyurethane resin composition is composed of lignin, which is a biomaterial, carbon dioxide emissions can be reduced.

[0012] [Aspect 2] The molecular weight of the polyol having an ethylene oxide chain as a basic skeleton is 100 or more and 600 or less. 2. The polyurethane resin composition according to claim 1.

[0013] According to this configuration, it is possible to set the Asker C hardness of the polyurethane resin composition to 50 or more and 90 or less. This contributes to the production of a polyurethane resin composition having a hardness suitable for use as a covering material for a steering wheel, for example.

[0014] [Aspect 3] The mass percent concentration of the filler in the polyurethane resin composition is 5 wt% or more and 25 wt% or less. 3. The polyurethane resin composition according to claim 1 or 2.

[0015] According to this configuration, it is possible to set the Asker C hardness of the polyurethane resin composition to 50 or more and 90 or less. This contributes to the production of a polyurethane resin composition having a hardness suitable for use as a covering material for a steering wheel, for example.

[0016] [Aspect 4] A core metal and a covering material made of the polyurethane resin composition according to aspect 2 or aspect 3 and covering the core metal; Steering wheel.

[0017] This configuration satisfies the hardness required for the covering material of the steering wheel. [Aspect 5] A method for producing a polyurethane resin composition by reacting an isocyanate component, a polyol component, and a filler, comprising: The polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, The filler is a modified lignin modified by bonding polyethylene glycol. A method for producing a polyurethane resin composition.

[0018] According to this method, the same effects as those of the polyurethane resin composition according to the first aspect can be achieved. [Effects of the Invention]

[0019] According to the present invention, it is possible to increase the hardness of a polyurethane resin composition while using a polyol having an ethylene oxide chain as the main skeleton as a polyol component. Furthermore, because the polyurethane resin composition is composed of lignin, which is a biomaterial, it is possible to reduce carbon dioxide emissions. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a table showing various data of examples of polyurethane resin compositions. [Figure 2] FIG. 2 is a table showing various data of comparative examples of polyurethane resin compositions. [Figure 3] FIG. 3 is a cross-sectional view of the steering wheel. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment will be described with reference to the drawings. As shown in FIG. 3, a steering wheel 10 for an automobile includes a core metal 11 and a covering material 12 made of a polyurethane resin composition and covering the core metal 11.

[0022] The polyurethane resin composition of the present embodiment and its production method will be described below. The polyurethane resin composition is formed by reacting an isocyanate component, a polyol component, and a filler.

[0023] The isocyanate component is a well-known isocyanate used in the production of polyurethanes. The polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, and the molecular weight of the polyol having an ethylene oxide chain as a basic skeleton is preferably 100 or more and 600 or less.

[0024] The filler is a modified lignin that has been modified by attaching polyethylene glycol (PEG). The mass percent concentration of the filler in the polyurethane resin composition is preferably 5 wt% or more and 25 wt% or less, and more preferably 8 wt% or more and 21 wt% or less.

[0025] In addition, the method for producing a polyurethane resin composition is a method for producing a polyurethane resin composition by reacting an isocyanate component, a polyol component, and a filler, where the polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, and the filler is modified lignin modified by bonding with PEG.

[0026] Next, with reference to FIG. 1, examples of polyurethane resin compositions will be described. (First Example) The polyurethane resin composition of the first embodiment contains, as polyol components, 12.4 wt% of PEG, a bifunctional polyol having an average molecular weight of 400, 18.6 wt% of PEG, a bifunctional polyol having an average molecular weight of 600, and 8.8 wt% of PEG, a trifunctional polyol having an average molecular weight of 430.

[0027] The polyurethane resin composition of the first example contains 41.1 wt% of isocyanate and 17.0 wt% of modified lignin. The polyurethane resin composition of Example 1 was excellent in moldability for urethane molding (evaluated as ⊚).

[0028] The Asker C hardness of the polyurethane resin composition of Example 1 was 60, which was within the Asker C hardness range of 50 or more and 90 or less, which is suitable for the covering material 12 (evaluation: ⊚). The polyurethane resin composition of Example 1 did not produce sink marks (evaluation: Excellent).

[0029] For these reasons, the polyurethane resin composition of Example 1 was overall evaluated as excellent. (Second Example) The polyurethane resin composition of the second example contains, as polyol components, 31.0 wt % of PEG, which is a difunctional polyol and has an average molecular weight of 200, and 8.8 wt % of PEG, which is a trifunctional polyol and has an average molecular weight of 430.

[0030] The polyurethane resin composition of the second example contains 41.1 wt% of isocyanate and 17.0 wt% of modified lignin. The polyurethane resin composition of Example 2 was excellent in moldability for urethane molding (evaluated as ⊚).

[0031] The Asker C hardness of the polyurethane resin composition of the second example was 90, which was within the Asker C hardness range of 50 or more and 90 or less that is suitable for the covering material 12 (evaluation: O). The polyurethane resin composition of Example 2 did not produce sink marks (evaluation: Excellent).

[0032] For these reasons, the polyurethane resin composition of Example 2 was overall evaluated as ⊚ to ◯. In the polyurethane resin composition of Example 2, the average molecular weight of the bifunctional polyol PEG is lower than that of Example 1, and therefore the bond distance between the polyol and the isocyanate is shorter, which is thought to have resulted in a higher Asker C hardness, i.e., a harder composition.

[0033] (Third Example) The polyurethane resin composition of the third example contains, as polyol components, 31.0 wt % of PEG, which is a difunctional polyol and has an average molecular weight of 400, and 8.8 wt % of PEG, which is a trifunctional polyol and has an average molecular weight of 430.

[0034] The polyurethane resin composition of the second example contains 41.1 wt% of isocyanate and 17.0 wt% of modified lignin. The polyurethane resin composition of Example 3 was excellent in moldability for urethane molding (evaluated as ⊚).

[0035] The Asker C hardness of the polyurethane resin composition of the third example was 83, which was within the Asker C hardness range of 50 or more and 90 or less, which is suitable for the covering material 12 (evaluation: ⊚). The polyurethane resin composition of Example 3 did not suffer from problematic sink marks (evaluation: Good).

[0036] For these reasons, the polyurethane resin composition of Example 3 was overall evaluated as ⊚ to ◯. Example 3 differs from Example 1 in that it uses a bifunctional polyol, PEG, with a single average molecular weight. This reduces the variation in polyurethane chain length, which is thought to make the resin softer immediately after molding and before hardening compared to Example 1, making it more susceptible to sink marks.

[0037] (Fourth Example) The polyurethane resin composition of Example 4 contains, as polyol components, 31.0 wt % of PEG, which is a difunctional polyol and has an average molecular weight of 600, and 8.8 wt % of PEG, which is a trifunctional polyol and has an average molecular weight of 430.

[0038] The polyurethane resin composition of the second example contains 41.1 wt% of isocyanate and 17.0 wt% of modified lignin. The polyurethane resin composition of Example 4 was excellent in moldability for urethane molding (evaluated as ⊚).

[0039] The Asker C hardness of the polyurethane resin composition of Example 4 was 53, which was within the Asker C hardness range of 50 or more and 90 or less that is suitable for the covering material 12 (evaluated as ⊚). The polyurethane resin composition of Example 4 did not suffer from problematic sink marks (evaluation: Good).

[0040] For these reasons, the polyurethane resin composition of Example 4 was overall evaluated as ⊚ to ◯. Example 4 differs from Example 1 in that it uses a bifunctional polyol, PEG, with a single average molecular weight. This reduces the variation in polyurethane chain length, which is thought to make the resin softer immediately after molding and before hardening compared to Example 1, making it more susceptible to sink marks.

[0041] (Fifth Example) The polyurethane resin composition of the fifth embodiment contains, as polyol components, 13.6 wt% of PEG, a bifunctional polyol having an average molecular weight of 400, 19.7 wt% of PEG, a bifunctional polyol having an average molecular weight of 600, and 10.0 wt% of PEG, a trifunctional polyol having an average molecular weight of 430.

[0042] The polyurethane resin composition of the first example contains 44.6 wt% of isocyanate and 10.0 wt% of modified lignin. The polyurethane resin composition of Example 5 was excellent in moldability for urethane molding (evaluated as ⊚).

[0043] The Asker C hardness of the polyurethane resin composition of Example 5 was 50, which was within the Asker C hardness range of 50 or more and 90 or less that is suitable for the covering material 12 (evaluated as ⊚). The polyurethane resin composition of Example 5 had sink marks (evaluation: Fair).

[0044] For these reasons, the polyurethane resin composition of Example 3 was overall evaluated as good. In the fifth example, the blending ratio of modified lignin was lower than in the first to fourth examples, and it is believed that the sink marks occurred because the resin became soft immediately after molding and before hardening.

[0045] (Sixth Example) The polyurethane resin composition of Example 6 contains, as polyol components, 11.1 wt% of PEG, a bifunctional polyol with an average molecular weight of 400, 17.2 wt% of PEG, a bifunctional polyol with an average molecular weight of 600, and 7.5 wt% of PEG, a trifunctional polyol with an average molecular weight of 430.

[0046] The polyurethane resin composition of the first example contains 37.1 wt% of isocyanate and 25.0 wt% of modified lignin. In the polyurethane resin composition of Example 6, the moldability of urethane molding was slightly inferior to Examples 1 to 5 (evaluation: ◯).

[0047] The Asker C hardness of the polyurethane resin composition of Example 6 was 90, which was within the Asker C hardness range of 50 or more and 90 or less that is suitable for the covering material 12 (evaluation: O). The polyurethane resin composition of Example 6 did not produce sink marks (evaluation: Excellent).

[0048] For these reasons, the polyurethane resin composition of Example 6 was overall evaluated as good. In Example 6, the amount of isocyanate blended was smaller but the amount of modified lignin blended was larger than in Examples 1 to 5. This is thought to be why the polyurethane resin composition became harder.

[0049] It should be noted that none of the polyurethane resin compositions of Examples 1 to 6 contain ethylene glycol (EG) or polypropylene glycol (PPG). Next, a comparative example of a polyurethane resin composition will be described with reference to FIG.

[0050] (First Comparative Example) The polyurethane resin composition of Comparative Example 1 contains, as polyol components, 31.0 wt % of EG, a difunctional polyol having an average molecular weight of 62, and 8.8 wt % of PEG, a trifunctional polyol having an average molecular weight of 430.

[0051] The polyurethane resin composition of the first comparative example contained 41.1 wt % of isocyanate and 17.0 wt % of modified lignin. In Comparative Example 1, urethane molding was not possible (evaluation: ×). Therefore, there are no measurement results for the Asker C hardness of the polyurethane resin composition of Comparative Example 1 (no evaluation).

[0052] The polyurethane resin composition of Comparative Example 1 did not produce sink marks (evaluation: Excellent). For these reasons, the polyurethane resin composition of Comparative Example 1 was overall evaluated as poor. In the first comparative example, it is believed that the modified lignin did not dissolve in EG, and therefore urethane molding was not possible.

[0053] (Second Comparative Example) The polyurethane resin composition of the second comparative example contains, as polyol components, 15.6 wt% of PEG, a bifunctional polyol having an average molecular weight of 400, 21.7 wt% of PEG, a bifunctional polyol having an average molecular weight of 600, and 11.0 wt% of PEG, a trifunctional polyol having an average molecular weight of 430.

[0054] The polyurethane resin composition of Comparative Example 2 contains 49.6 wt % of isocyanate and does not contain modified lignin. In the polyurethane resin composition of Comparative Example 2, the moldability of urethane molding was slightly inferior to that of Examples 1 to 5 (evaluation: ◯).

[0055] The Asker C hardness of the polyurethane resin composition of Comparative Example 2 was 25, which was outside the Asker C hardness range of 50 or more and 90 or less that is suitable for the covering material 12 (evaluation: Fair).

[0056] The polyurethane resin composition of Comparative Example 2 had problematic sink marks (evaluation: ×). For these reasons, the polyurethane resin composition of Comparative Example 2 was overall evaluated as poor.

[0057] In Comparative Example 2, since no modified lignin was contained, it is believed that the polyurethane resin composition became too soft. (Third Comparative Example) The polyurethane resin composition of Comparative Example 3 contains, as polyol components, 16.6 wt% of PEG, which is a bifunctional polyol and has an average molecular weight of 400, and 23.2 wt% of PEG, which is a bifunctional polyol and has an average molecular weight of 600. The polyurethane resin composition of Comparative Example 3 does not contain PEG, which is a trifunctional polyol and has an average molecular weight of 430.

[0058] The polyurethane resin composition of the first comparative example contained 41.1 wt % of isocyanate and 17.0 wt % of modified lignin. In the polyurethane resin composition of Comparative Example 3, the moldability of urethane molding was slightly inferior to that of Examples 1 to 5 (evaluation: ◯).

[0059] The Asker C hardness of the polyurethane resin composition of the third comparative example was 65, which was within the Asker C hardness range of 50 or more and 90 or less, which is suitable for the covering material 12 (evaluation: ⊚). The polyurethane resin composition of Comparative Example 3 had problematic sink marks (evaluation: ×).

[0060] For these reasons, the polyurethane resin composition of Comparative Example 3 was overall evaluated as poor. In Comparative Example 3, the trifunctional polyol did not contain PEG with an average molecular weight of 430, which is thought to have caused aggregation of PEG molecules, which is a bifunctional polyol, and this is thought to have caused the problematic sink marks.

[0061] (Fourth Comparative Example) The polyurethane resin composition of Comparative Example 4 contains, as polyol components, 31.0 wt% of PPG, a bifunctional polyol having an average molecular weight of 400, and 8.8 wt% of PEG, a trifunctional polyol having an average molecular weight of 430. The polyurethane resin composition of Comparative Example 4 does not contain PEG, which is a bifunctional polyol.

[0062] The polyurethane resin composition of the fourth comparative example contained 41.1 wt % of isocyanate and 17.0 wt % of modified lignin. In Comparative Example 4, urethane molding was not possible (evaluation: ×). Therefore, there were no measurement results for Asker C hardness and evaluation results for sink marks for the polyurethane resin composition of Comparative Example 4 (evaluation: no).

[0063] The polyurethane resin compositions of Examples 1 to 6 and Comparative Examples 1 to 4 contain 1.1 wt % of a known reaction catalyst and 1.0 wt % of a known weatherproofing agent. Furthermore, PEG contained in the modified lignin contributes to the reaction that occurs when polyurethane is formed. Therefore, in the above examples and comparative examples, when determining the amount of isocyanate to be blended, not only the bifunctional polyol and trifunctional polyol but also the PEG contained in the modified lignin is considered as a polyol that reacts with isocyanate.

[0064] Next, the effects of this embodiment will be described. (1) In a polyurethane resin composition, when the polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, the hardness is lower than when the polyol component mainly contains a polyol having a propylene oxide chain as a basic skeleton.

[0065] According to the above configuration, the modified lignin filler is modified by bonding PEG to the lignin. Furthermore, the lignin constituting the modified lignin has high hardness due to the presence of a benzene ring. This increases the hardness of the polyurethane resin composition. This is thought to be because, when the polyurethane resin composition is formed, the OH groups of the modified lignin react to bond polyurethane chains together, limiting the degree of freedom of deformation of the polyurethane chains.

[0066] Therefore, the hardness of the polyurethane resin composition can be increased even though the polyol component mainly uses a polyol having an ethylene oxide chain as the basic skeleton. Furthermore, because the polyurethane resin composition is composed of lignin, which is a biomaterial, carbon dioxide emissions can be reduced.

[0067] (2) Because the molecular weight of the polyol having an ethylene oxide chain as a basic skeleton is 100 or more and 600 or less, it is possible to set the Asker C hardness of the polyurethane resin composition to 50 or more and 90 or less. This contributes to the production of a polyurethane resin composition having a hardness suitable for use as the covering material 12 of the steering wheel 10, for example.

[0068] (3) Since the mass percent concentration of the filler in the polyurethane resin composition is 5 wt% or more and 25 wt% or less, it is possible to set the Asker C hardness of the polyurethane resin composition to 50 or more and 90 or less. This contributes to the production of a polyurethane resin composition having a hardness suitable for use as the covering material 12 of the steering wheel 10, for example.

[0069] (5) The steering wheel 10 includes a core 11 and a covering material 12 made of a polyurethane resin composition and covering the core 11. With this configuration, the covering material 12 of the steering wheel 10 can meet the hardness required.

[0070] (6) A method for producing a polyurethane resin composition includes reacting an isocyanate component, a polyol component, and a filler to produce the polyurethane resin composition. In the method, the polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton. The filler is modified lignin modified by bonding PEG.

[0071] This method can achieve the same effect as (1). <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0072] The polyurethane resin composition can also be used for purposes other than the covering material 12 of the steering wheel 10. The weight percent concentration of the filler in the polyurethane resin composition may be less than 5 wt %, or more than 25 wt %.

[0073] The molecular weight of the polyol having an ethylene oxide chain as a basic skeleton, which is mainly contained in the polyol component, may be less than 100. Also, the molecular weight of the polyol having an ethylene oxide chain as a basic skeleton, which is mainly contained in the polyol component, may be greater than 600.

[0074] The polyurethane resin composition and the method for producing a polyurethane resin composition according to the present invention do not exclude the inclusion of a polyol having a propylene oxide chain as a basic skeleton. In other words, the polyurethane resin composition and the method for producing a polyurethane resin composition may contain a polyol having a propylene oxide chain as a basic skeleton, as long as it mainly contains a polyol having an ethylene oxide chain as a basic skeleton. [Explanation of symbols]

[0075] 10...Steering wheel 11...Core 12...Coating material

Claims

1. A polyurethane resin composition formed by reacting an isocyanate component, a polyol component, and a filler, The polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, The filler is a modified lignin modified by bonding polyethylene glycol. Polyurethane resin composition.

2. The molecular weight of the polyol having an ethylene oxide chain as a basic skeleton is 100 or more and 600 or less. The polyurethane resin composition according to claim 1.

3. The mass percent concentration of the filler in the polyurethane resin composition is 5 wt % or more and 25 wt % or less. The polyurethane resin composition according to claim 2.

4. A core wire and a coating material made of the polyurethane resin composition according to claim 2 or 3 and coating the core metal, Steering wheel.

5. A method for producing a polyurethane resin composition by reacting an isocyanate component, a polyol component, and a filler, comprising: The polyol component mainly contains a polyol having an ethylene oxide chain as a basic skeleton, The filler is a modified lignin modified by bonding polyethylene glycol. A method for producing a polyurethane resin composition.

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