Base fabric, airbag, and method for manufacturing the base fabric

Abstract

To provide a base fabric that can reduce carbon dioxide emissions during manufacturing. [Solution] The base fabric comprises a substrate and a coating layer containing an acrylic resin paint that coats the surface of the substrate.

Description

Technical Field

[0001] The present disclosure relates to a base fabric, an airbag, and a method for manufacturing the base fabric.

Background Art

[0002] Various base fabrics having a coating on the surface have been proposed. For example, Patent Document 1 discloses a base fabric coated with a silicone-based paint as a coating agent.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, it has been required to reduce carbon dioxide emissions in the manufacturing industry. Silicone has a relatively large amount of carbon dioxide emissions in manufacturing. Therefore, there is a need for a base fabric that can reduce the overall carbon dioxide emissions in manufacturing.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, a base fabric is provided. The base fabric includes a base material and a coating layer that includes an acrylic resin paint and coats the surface of the base material. Since the base fabric of this aspect includes a coating layer that includes an acrylic resin paint and coats the surface of the base material, the overall carbon dioxide emissions in the production of the base fabric can be reduced as compared with a configuration in which the coating layer does not include an acrylic resin paint and consists only of a silicone-based paint. (2) In the base fabric of the above form, the acrylic resin coating may be a two-component type. With this type of base fabric, the acrylic resin coating is a two-component type, which suppresses the deterioration of the coating layer in high-temperature and high-humidity environments compared to a one-component acrylic resin coating. (3) In the base fabric of the above form, the acrylic resin coating does not need to contain isocyanate as a curing agent. With this type of base fabric, the acrylic resin coating does not contain isocyanate as a curing agent, thus allowing for a longer curing time for the coating layer compared to a configuration where the acrylic resin coating contains isocyanate as a curing agent. This prevents the viscosity of the acrylic resin coating from increasing during the application process to the substrate, which can make application difficult. It also prevents clogging of the coating equipment and makes it easier to adjust the thickness of the coating layer. (4) In the base fabric of the above form, the curing agent includes a compound having an aliphatic main chain and an epoxy group as a functional group, and the number of epoxy groups in the compound may be 3 to 4. With this type of base fabric, the curing agent contains a compound whose main chain is aliphatic. Compared to a configuration where the curing agent does not contain a compound whose main chain is aliphatic but contains a compound whose main chain is aromatic, this configuration helps to suppress a decrease in the usability of the base fabric. Specifically, when a compound whose main chain is aromatic is used as the curing agent, the coating layer becomes relatively hard. In contrast, by including a compound whose main chain is aliphatic in the curing agent, the durability can be improved while maintaining the flexibility of the base fabric, thus suppressing a decrease in the usability of the base fabric. Furthermore, since the number of epoxy groups in the compound is 3 to 4, it is possible to suppress the decrease in the usability of the base fabric compared to compositions with fewer than 3 or more than 4 epoxy groups in the compound. Specifically, if a compound with fewer than 3 epoxy groups is used as a curing agent, the durability will be insufficient. Also, if a compound with more than 4 epoxy groups is used as a curing agent, the coating layer will become excessively hard, and the flexibility of the base fabric will decrease. In contrast, by including a compound with 3 to 4 epoxy groups in the curing agent, it is possible to improve durability while maintaining the flexibility of the base fabric, and suppress the decrease in the usability of the base fabric.

[0007] This disclosure can be implemented in various forms. For example, it can be implemented in the form of an airbag using a base fabric, a method for manufacturing a base fabric, etc. [Brief explanation of the drawing]

[0008] [Figure 1] This flowchart shows the procedure for a method of manufacturing a base fabric in one embodiment of the present disclosure. [Figure 2] This table shows the results of the environmental resistance test. [Modes for carrying out the invention]

[0009] A. Embodiments: The base fabric in this disclosure is used in airbags installed in vehicles. When a vehicle collision is detected or predicted, the airbag inflates and deploys using gas supplied from an inflator to reduce the impact on the occupants. The airbag has a bag-like external shape. The airbag is manufactured by sewing together one or more pieces of base fabric.

[0010] The base fabric comprises a substrate and a coating layer. The substrate is a woven fabric containing synthetic fibers. The synthetic fibers are manufactured from, for example, polyamide resins, polyester resins, or aramid resins. An example of a polyamide resin is nylon 6,6. An example of a polyester resin is polyethylene terephthalate.

[0011] The coating layer coats the surface of the substrate. The coating layer prevents gas supplied into the substrate fabric from passing through the gaps between the fibers of the substrate and leaking out to the outside. The coating layer in this disclosure includes an acrylic resin paint. The acrylic resin paint in this embodiment is a two-component type. The acrylic resin paint in other embodiments is a one-component type. In this disclosure, a two-component acrylic resin paint means an acrylic resin paint containing a curing agent, and a one-component acrylic resin paint means an acrylic resin paint that does not contain a curing agent. The acrylic resin paint may further contain a thickening agent.

[0012] The main component contains an acrylic acid ester. Examples of acrylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate. The main component is produced by adding an emulsifier and a reaction initiator to the acrylic acid ester and performing emulsion polymerization. Examples of emulsifiers used for emulsion polymerization include anionic, nonionic, and cationic types.

[0013] The curing agent includes compounds whose main chain is aliphatic and which have epoxy groups as functional groups. Examples of such compounds include polyglycerol polyglycidyl ether, pentaerythritol tetraglycidyl ether, trimethylolpropane triglycidyl ether, glycerol triglycidyl ether, sorbitol polyglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polypropylene glycol diglycidyl ether, diglycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and resorcinol diglycidyl ether. The number of epoxy groups in the compound is preferably 3 to 4. The curing agent preferably does not contain compounds whose main chain is aromatic. The curing agent in this embodiment does not contain isocyanates. The curing agent in other embodiments contains isocyanates.

[0014] In this embodiment, the viscosity of the acrylic resin coating before application is preferably 20,000 mPa·s to 200,000 mPa·s. The viscosity is measured using a Type B viscometer (manufactured by Toki Sangyo Co., Ltd.) with a No. 4 rotor attached, at a temperature of 23°C and a rotation speed of 1.0 rpm to 20 rpm. The viscosity is adjusted by adding a thickening agent.

[0015] B. Method for manufacturing the base fabric: Figure 1 is a flowchart showing the steps for a method of manufacturing a base fabric in one embodiment of the present disclosure. The method of manufacturing the base fabric includes a preparation step (P110) and a coating step (P120). It is performed as one step in the manufacturing process of an airbag.

[0016] In the preparation step (P110), the substrate and the acrylic resin paint are prepared. The main component and hardener of the two-component acrylic resin paint are pre-mixed. In the preparation step (P110), the viscosity of the acrylic resin paint may be adjusted.

[0017] In the coating process (P120), an acrylic resin paint is applied to the substrate. The application is performed, for example, by knife coating using a coating device. Through the coating process (P120), a coating layer is formed on the surface of the substrate.

[0018] C. Comparison between two-component acrylic resin paint and one-component acrylic resin paint: FIG. 2 is a table showing the results of the environmental resistance test. An environmental resistance test was conducted using the base fabric of Example 1 obtained according to this embodiment and the base fabric of Example 2 obtained according to another embodiment. The base fabric of Example 1 was manufactured using a two-component acrylic resin paint. Specifically, an acrylic emulsion composed of an acrylate ester and an emulsifier as the main agent, a reaction initiator, an antifoaming agent, a preservative, and a film-forming aid were mixed and used. The acrylate ester used was a mixture of acrylic acid, methyl methacrylate, n-butyl acrylate, methacrylamide, and ethylene glycol dimethacrylate. Also, polyglycerol polyglycidyl ether was used as the curing agent. The base fabric of Example 2 was manufactured using a one-component acrylic resin paint. That is, in Example 2, a coating layer was formed using the same main agent as in Example 1 without using a curing agent.

[0019] The environmental resistance test was conducted by two tests. The first test was conducted by observing the change in the coating layer of the base fabric placed in a high-temperature environment. Specifically, the base fabric was folded so that the coating layers were in contact with each other, and a weight was placed on it. This base fabric was left standing in an environment of 120°C for 400 hours, and the presence or absence of adhesion between the coating layers was observed. As a result, as shown in the upper part of FIG. 2, the base fabric of Example ① was not adhered. In contrast, the base fabric of Example ② had the coating layers adhered to each other. That is, the coating layer had deteriorated.

[0020] It should be noted that there seems to be a mistake in the original text where "実施例1の基布は、2液型アクリル系樹脂塗料を用いて製造した。具体的には、主剤としてアクリル酸エステルおよび乳化剤からなるアクリルエマルションと、反応開始材と、消泡剤と、防腐剤と、造膜助剤と、を混合したものを用いた。アクリル酸エステルは、アクリル酸と、メタクリル酸メチルと、アクリル酸n-ブチルと、メタクリルアミドと、ジメタクリル酸エチレングリコールとを混合したものを用いた。また、硬化剤として、ポリグリセロールポリグリシジルエーテルを用いた。" is translated as "実施例1の基布は、2液型アクリル系樹脂塗料を用いて製造した。具体的には、主剤としてアクリル酸エステルおよび乳化剤からなるアクリルエマルションと、反応開始材と、消泡剤と、防腐剤と、造膜助剤と、を混合したものを用いた。アクリル酸エステルは、アクリル酸と、メタクリル酸メチルと、アクリル酸n-ブチルと、メタクリルアミドと、ジメタクリル酸エチレングリコールとを混合したものを用いた。また、硬化剤として、ポリグリセロールポリグリシジルエーテルを用いた。" in the English translation. There may be some confusion in the reference numbers in the original text. Also, "実施例2の基布は、1液型アクリル系樹脂塗料を用いて製造した。すなわち、実施例2においては、硬化剤を用いずに、実施例1と同様の主剤を用いてコーティング層を形成した。" is translated as "実施例2の基布は、1液型アクリル系樹脂塗料を用いて製造した。すなわち、実施例2においては、硬化剤を用いずに、実施例1と同様の主剤を用いてコーティング層を形成した。" with the same potential reference number issue. And in the translation of "耐環境性試験は、2つの試験により行った。第1試験は、高温環境に置かれた基布のコーティング層の変化を観察することにより行われた。具体的には、コーティング層同士が接するように基布を折り重ね、その上に重りを乗せた。この基布を120℃の環境に400時間静置し、コーティング層同士の接着の有無を観察した。この結果として、図2の上段に示すように、実施例1の基布は、接着していなかった。これに対して、実施例2の基布は、コーティング層同士が接着していた。すなわち、コーティング層が劣化していた。", there is a reference number "①" and "②" in the translated text which seem to be incorrect in the context. It's recommended to double-check and correct these reference numbers in the original text for a more accurate translation.The second test was conducted by observing the change in the coating layer of the base fabric placed in a humid environment. Specifically, the base fabric was folded so that the coating layers contacted each other, and a weight was placed on it. This base fabric was left standing in an environment of 80°C and 95% humidity for 400 hours, and the presence or absence of adhesion between the coating layers was observed. As a result, as shown in the lower part of FIG. 2, the base fabric of Example 1 was not adhered. On the other hand, the base fabric of Example 2 had the coating layers adhered to each other. That is, the coating layer had deteriorated.

[0021] From the results of the two environmental resistance tests, it was suggested that the deterioration of the base fabric of Example 1 was suppressed more than that of the base fabric of Example 2 in a high-temperature environment and a humid environment. That is, it was suggested that the two-component acrylic resin paint can form a coating layer with better environmental resistance than the one-component acrylic resin paint.

[0022] D. Comparison between a curing agent containing isocyanate and a curing agent not containing isocyanate: Using the curing agent of Example 3 and the curing agent of Example 4, a curing test of the acrylic resin paint was conducted. The curing agent of Example 1 did not contain isocyanate as the curing agent as in the above embodiment. Specifically, polyglycerol polyglycidyl ether was used as the curing agent. In Example 4, isocyanate was used as the curing agent as in other embodiments. Isocyanate is generally used as a curing agent for acrylic resin paints. In Example 3 and Example 4, as the main agent, a mixture of an acrylic emulsion composed of an acrylate ester and an emulsifier, a reaction initiator, an antifoaming agent, a preservative, and a film-forming aid was used. The acrylate ester used was a mixture of acrylic acid, methyl methacrylate, n-butyl acrylate, methacrylamide, and ethylene glycol dimethacrylate.

[0023] The curing test was performed by observing the change in viscosity of the acrylic resin paint over time after adding the curing agent to the main component. After adding the curing agent to the main component, the mixture was left to stand in an environment of 23°C. Viscosity was measured under the same conditions as in the above embodiment. The viscosity of the acrylic resin paint using the curing agent of Example 3 remained almost unchanged from immediately after adding the curing agent until 24 hours later, at 89,000 mPa·s. In contrast, the viscosity of the acrylic resin paint using the curing agent of Example 4 was 1,400 mPa·s at the time of curing agent addition, and reached 16,000 mPa·s 4 hours after curing agent addition, showing a rapid increase in viscosity from 4 hours later. Furthermore, a large amount of foaming was observed from 4 hours later. At 6 hours later, curing had progressed, and viscosity could not be measured.

[0024] The curing test results suggest that using an isocyanate-free curing agent, as in Example 3, allows for a longer curing time for acrylic resin coatings compared to curing agents containing isocyanates. This suggests that using an isocyanate-free curing agent improves convenience in base fabric manufacturing when forming a coating layer on a base fabric using a two-component acrylic resin coating. Specifically, in configurations using curing agents containing isocyanates, the curing time for the coating is relatively short, which may lead to an increase in the viscosity of the coating during the application process, making application impossible; a risk of the coating hardening in the application equipment and clogging; or a risk of the coating hardening on the substrate during the application process, making it impossible to adjust the thickness of the coating layer. In contrast, using an isocyanate-free curing agent, as in Example 3, allows for a relatively longer curing time for the coating, thus suppressing an increase in the viscosity of the coating during the application process; suppressing the hardening of the coating in the application equipment; and suppressing the hardening of the coating on the substrate during the application process. This improves convenience in base fabric manufacturing.

[0025] According to the base fabric and base fabric manufacturing method of the embodiments described above, since the coating layer contains an acrylic resin paint, the overall carbon dioxide emissions in the manufacturing of the base fabric can be reduced compared to a configuration in which the coating layer does not contain an acrylic resin paint and consists only of a silicone resin paint.

[0026] Furthermore, in a two-component acrylic resin coating configuration, degradation in high-temperature and high-humidity environments can be suppressed compared to a one-component configuration.

[0027] Furthermore, in a two-component acrylic resin paint configuration that does not contain isocyanate as a curing agent, the curing time can be extended compared to a configuration that includes isocyanate as a curing agent. This prevents the viscosity of the two-component acrylic resin paint from increasing during the application process to the substrate, which can make application difficult. It also prevents clogging of the paint application equipment. In addition, it makes it easier to adjust the thickness of the coating layer.

[0028] Furthermore, since the curing agent contains a compound whose main chain is aliphatic, it is possible to suppress a decrease in the usability of the base fabric compared to a configuration in which the curing agent does not contain a compound whose main chain is aliphatic but contains a compound whose main chain is aromatic. Specifically, when a compound whose main chain is aromatic is used as the curing agent, the coating layer becomes relatively hard. In contrast, in this embodiment, since the curing agent contains a compound whose main chain is aliphatic, it is possible to improve durability while maintaining the flexibility of the base fabric, and suppress a decrease in the usability of the base fabric.

[0029] Furthermore, since the number of epoxy groups in the compounds contained in the curing agent is 3 to 4, it is possible to suppress the decrease in the usability of the base fabric compared to compositions with fewer than 3 or more than 4 epoxy groups. Specifically, compounds with fewer than 3 epoxy groups do not provide sufficient durability. Also, compounds with more than 4 epoxy groups result in an excessively hard coating layer, reducing the flexibility of the base fabric. In contrast, in this embodiment, since the number of epoxy groups is 3 to 4, durability can be improved while maintaining the flexibility of the base fabric, and a decrease in the usability of the base fabric can be suppressed.

[0030] Furthermore, since the viscosity of the acrylic resin coating before application is between 20,000 mPa·s and 200,000 mPa·s, compared to a configuration with a viscosity of less than 20,000 mPa·s, the acrylic resin coating is less likely to penetrate between the fibers of the substrate, and excessive hardening of the base fabric can be suppressed. Also, compared to a configuration with a viscosity exceeding 200,000 mPa·s, the difficulty in applying the acrylic resin coating to the substrate due to excessive viscosity can be suppressed.

[0031] E. Other embodiments: (E1) In the above embodiment, the curing agent contained a compound having an aliphatic main chain and an epoxy group as a functional group, and the number of epoxy groups in the compound was 3 to 4, but the disclosure is not limited thereto. The curing agent may contain any compound. Even with such a configuration, the overall carbon dioxide emissions in the manufacture of the base fabric can be reduced compared to a configuration in which the coating layer consists only of a silicone resin coating and does not contain an acrylic resin coating.

[0032] (E2) In the above embodiments, the viscosity of the acrylic resin coating before application was 20,000 mPa·s to 200,000 mPa·s, but the disclosure is not limited thereto. The viscosity of the acrylic resin coating before application may be less than 20,000 mPa·s or greater than 200,000 mPa·s. Even with such a configuration, carbon dioxide emissions in the manufacture of the base fabric can be reduced compared to a configuration in which the coating layer consists only of a silicone resin coating and does not contain an acrylic resin coating.

[0033] (E3) In the above embodiment, the curing agent may contain multiple compounds. In such a configuration, the number of epoxy groups may be the average value of the multiple compounds. For example, if the curing agent is composed of a first compound having 2 epoxy groups and a second compound having 5 epoxy groups, and the amount of substance of the first compound and the amount of substance of the second compound contained in the cured product are equal, the number of epoxy groups is treated as 3.5. In this way, by setting the average number of epoxy groups in the multiple compounds to 3 to 4, the deterioration of the usability of the base fabric can be suppressed, similar to the above embodiment.

[0034] (E4) In the above embodiments, the base fabric was used in an airbag, but the disclosure is not limited thereto. The base fabric may be used in any component.

[0035] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

Claims

1. It is a base fabric, Substrate and A coating layer comprising an acrylic resin paint and coating the surface of the substrate, A base fabric having the following features.

2. The base fabric according to claim 1, The aforementioned acrylic resin coating is a two-component type, and the base fabric is...

3. The base fabric according to claim 2, The aforementioned acrylic resin coating is a base fabric that does not contain isocyanate as a hardening agent.

4. The base fabric according to claim 3, The curing agent comprises a compound having an aliphatic main chain and an epoxy group as a functional group, A base fabric in which the number of epoxy groups in the compound is 3 to 4.

5. An airbag using the base fabric described in any one of claims 1 to 4.

6. A method for manufacturing a base fabric, Preparation process for the base material and acrylic resin paint, A coating step of applying the acrylic resin paint to the surface of the substrate to form a coating layer, A method for manufacturing a base fabric, comprising the following features.

7. A method for manufacturing a base fabric according to claim 6, The aforementioned acrylic resin coating is a two-component type, and the method for manufacturing a base fabric.

8. A method for manufacturing a base fabric according to claim 7, The acrylic resin coating is a method for manufacturing a base fabric that does not contain isocyanate as a curing agent.

9. A method for manufacturing a base fabric according to claim 8, The curing agent comprises a compound having an aliphatic main chain and an epoxy group as a functional group, A method for producing a base fabric, wherein the number of epoxy groups in the compound is 3 to 4.

10. A method for manufacturing a base fabric according to any one of claims 6 to 9, A method for manufacturing a base fabric, wherein the viscosity of the acrylic resin coating prepared in the above preparation step is 20,000 mPa·s to 200,000 mPa·s.

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