JPH042889A - Surface treatment of artificial leather - Google Patents

Abstract

PURPOSE:To carry out surface treatment for giving a visual appearance and touch similar to a natural leather by coating an artificial leather with a polyamino acid urethane resin using a solvent having a swelling effect to the artificial leather, then curing the resin, subsequently carrying out crepe treatment and furthermore applying a surface treatment agent thereto. CONSTITUTION:An artificial leather is coated with a surface treatment solution prepared by dissolving a polyamino acid urethane resin as a surface treatment agent in a dimethylformamide (swelling agent) and further adding a curing agent thereto. The above-mentioned resin is cured by drying with heating and crepe treatment is then carried out at 130-230 deg.C using a crepe roll. After application of a polyamino acid urethane resin having an excellent touch to the raised part of the above-mentioned dried resin or without the above-mentioned application, crepe treatment is carried out at 130-230 deg.C using a crepe roll 4 compose of a dented part 7 having a surface roughness of R0=10-70mum as average toughness of center line and a raised part 6 having a roughened surface, thus obtaining the objective artificial leather having a visual appearance and touch similar to a natural leather.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for surface treatment of artificial leather to give it the appearance and feel of genuine leather.

The term "artificial leather" as used herein refers to synthetic leather and artificially manufactured leather including artificial leather.

(Prior Art) Conventional surface treatments for artificial leather include, for example, those shown in FIG. In the illustrated method, in the first step, artificial leather 1 with a flat surface, such as soft polyvinyl chloride PVC leather, is supplied, and in the second step, the artificial leather 1 is
Using a roll (shibo roll) that maintains the unevenness by applying heat to ℃, the artificial leather is subjected to a graining process to give it an uneven surface. Furthermore, in the third step, the surface treatment agent 2 is applied to the entire surface of the artificial leather or only to the convex portions using another roll (surface treatment agent application roll) coated with the surface treatment agent.

(Problems to be Solved by the Invention) However, in such conventional surface treatment methods for artificial leather, a base material mainly made of vinyl chloride or urethane is subjected to a grain treatment, and a base material made of acrylic or urethane is Since the method used was to apply a surface treatment agent such as a surface treatment agent, depending on the selection of the surface treatment agent, it is possible to improve the appearance or feel, but it is not sufficient, and it is not possible to have both. . Therefore, polyamino acid urethane resin (PAD) containing amino acids with excellent texture
However, amino acid-based surface treatment agents generally tend to damage artificial leather due to their solvent nature, and when applied, they cause the base material to swell, making it impossible to improve the leather-like appearance.

(Means for Solving the Problem) As a result of intensive research to solve the above conventional problems, the inventor used polyamino acid urethane resin (PAU) as a surface treatment agent to directly treat artificial leather, and swelled the artificial leather. The present invention was based on the discovery that artificial leather having the appearance and feel of genuine leather can be obtained by a surface treatment method that includes a step of applying a solution of PAD dissolved in a solvent to artificial leather, drying it, and then graining it. has been achieved.

The method for surface treatment of artificial leather according to the first aspect of the present invention is to apply polyamino acid urethane resin (PA) as a surface treatment agent to the artificial leather.
U) is coated using a solvent that swells the artificial leather, dried to harden the PAU, grained at a temperature of 130 to 230°C, and further coated with a surface treatment agent.

Moreover, in the surface treatment method for artificial leather according to the second aspect of the present invention, after applying PAU to the artificial leather using a solvent that swells the artificial leather and drying it, the concave portion of the grain roll has a center line average roughness Ra= It is characterized by graining at 130 to 230°C using a roll finished to 10 to 70 μm and having roughened protrusions.

Artificial leathers that can be treated with the surface treatment method of this invention include polyvinyl chloride (PVC), urethane, and nylon artificial leathers, which are inexpensive and have industrial significance in improving visual and tactile sensations. Therefore, the explanation will be given below mainly using PVC-based artificial leather as an example.

In the artificial leather surface treatment method of the present invention, for example, dimethylformamide (DMF) is used as a solvent for swelling the artificial leather, and a solution in which PAD is dissolved is applied to the surface of the artificial leather. At this time, it is preferable to add a curing agent together with PAD to the DMF solution in which PAtl is dissolved. At this point, the surface of the artificial leather swells, so the artificial leather loses its unnatural (like artificial leather) surface luster caused by mechanical processing. Then preferably about 100°C
The surface treatment agent PAD is dried to volatilize the solvent and harden the surface treatment agent PAD with a hardening agent. The thickness of PAtl in a state in which DMF is volatilized is preferably 5 to 15 μm.

In the surface treatment method of the first invention, graining is then performed at a temperature of 130 to 230°C using a graining roll, and PAD with excellent texture or another surface treatment agent with excellent texture is applied onto the newly hardened PAU. A separate surface treatment agent application roll is used to apply the surface treatment agent to the entire surface of the grained artificial leather or only to the convex portions to improve the leather-like appearance and feel.

Next, in the surface treatment method of the second invention, the artificial leather that has been treated in the same manner as the surface treatment method of the first invention until the graining process is applied to the concave portions (the convex portions after being transferred to the artificial leather) are divided into center line average roughness. Using a grain roll finished with a surface roughness of Ra = 10 to 70 μ- and roughened on the convex portions (the portions become concave portions after transfer), artificial leather with PAD applied to the surface was coated with 13
It is grained at a temperature of 0 to 230°C and dried at room temperature. The concave and convex parts of the grain roll are originally smooth, so the convex parts of the roll that correspond to the concave parts of the product are made to have roughness, so that the difference in luster can be obtained between the top and valley of the product during graining. Roughness processing is applied to the convex part.

The surface-treated artificial leather as described above has both the appearance and feel of genuine leather.

(Example) This invention will be explained by the following examples, comparative examples, and reference examples.

1 1-3 PVC-based artificial leather was surface-treated according to the steps shown in FIG. 1(a). In the first step, artificial leather 1 was prepared. In the second step, a surface treatment agent solution was prepared as shown below. Add dimethylformamide (DMF) to polyamino acid urethane resin (PAU) stock solution (17% by weight DMF solution)
was stirred while adding and diluted to obtain an 8.5% by weight DMF solution. This solution is then further added with a curing agent [GP 10
5 A (manufactured by Mitsubishi Kasei Corporation)] in weight ratio, PAD:
It was added with stirring at a ratio of cp 105A=19:1. The resulting surface treatment agent solution was applied as the first layer surface treatment agent 2 to the artificial leather in the first step. In the third step, it was heated and dried at about 100° C. to volatilize the solvent and harden the surface treatment agent PAU with the hardening agent. Then the fourth
In the process, using the grain roll 4 shown in FIG. 1(b), 190
Textured at ℃. Next, in the fifth step, using another surface treatment agent coating roll 5 shown in FIG. 1(c),
In the fourth step, PAD that was easy to touch was applied as a second layer surface treatment agent to the areas above the convex portions of the dry PAD of the leather that had been grained. In this way, artificial leather with improved leather-like appearance and feel was obtained.

A surface treatment agent other than PAU having excellent texture can be applied as a second layer surface treatment agent on the PAD of the first layer surface treatment agent. Furthermore, although the second layer surface treatment agent was applied only to the convex portions, it may be applied to the entire surface as required.

SP is generally used as a solvent for surface treatment agents that improve the tactile sensation.
The value (solubility parameter) is similar to that of PvC (for example, SP (PVC) = 9.5 to 9.7, SP (DMF
) = 12.0), and materials that swell PvC are often used. In this case - skin surface treatment agent PAU
Since it cures and does not affect the PVC layer, it is possible to use surface treatment agents with excellent texture that require such solvents.

Next, genuine leather was treated with the first layer surface treatment agent shown in Table 1 (reference example), and PVC synthetic leather was treated in the same manner with the first layer surface treatment agent of Example 1. Artificial leather on which no second-layer surface treatment agent was applied (Comparative Example 1), ° Vinyl chloride/acrylic surface treatment agent was used as the first layer surface treatment agent, and methyl ethyl ketone (MEK): l-luene:
Leather dissolved in a mixed solvent of cyclohexane = 40: 40: 1O, applied as a 20% solution on a substrate with a shibo roll, and dried at 60°C for 20 seconds (Comparative Example 2), and untreated PVC The synthetic leather (Comparative Example 3), along with the artificial leather of Example 1, was evaluated for its leather-like appearance and leather-like feel using the following ratings, and the obtained results are also listed in Table 1.

Rating 5: Leather itself 4: Leather-like 3: Slightly leather-like 2: Not very leather-like 1: Not leather-like at all The same treatment as that up to step 3 was performed.At this time, the hardened PA
The thickness of U was 10 μm. Next, in the fourth step, the cowhide grain is made of cowhide leather having concave portions 7 with a center line average roughness Ra of 40 μm as shown in FIG. The material was subjected to a graining process at 190°C using a graining roll onto which the image was transferred, and then dried at room temperature. Table 2 shows the feel and appearance of leather that has been surface-treated in this way.

Next, leather was surface-treated in the same manner as in Example 2, except that the protrusions of the grain roll were not roughened (Comparative Example 4).
), instead of the surface treatment agent solution of Example 2, a urethane resin containing no amino acid was used instead of PADO as the surface treatment agent, and a mixed solvent of MEK and cyclohexane was used instead of DMF as the solvent, so that the solid content concentration was 15 weight. % solution was used as the surface treatment agent solution (Comparative Example 5), and a grain roll that remained smooth without roughness in the recesses of the grain roll. Example 2
The results were evaluated in the same way as in Table 1, and the results are shown in Table 2.

Table 2 (Effects of the Invention) As explained above, in this invention, polyamino acid urethane resin (PAU) is used as a surface treatment agent on the surface of artificial leather, and artificial leather such as dimethylformamide (Dl'lF) is applied to the surface of artificial leather. The first layer surface treatment agent is applied using a solvent that swells the PAU, and after drying and curing the PAU, it is grained with a grain roll at a predetermined temperature, and a new surface treatment agent with excellent texture is applied to the second layer. Apply as a surface treatment agent or
Alternatively, after applying a surface treatment agent and drying it to harden the PAD, it is finished with a surface roughness of center line average roughness Ra = 10 to 70 μm and is grained using a graining roll that has been roughened on the convex portions. By using a structure that involves processing, in addition to the surface treatment agent, a solvent that swells the artificial leather removes the unnatural luster that the artificial leather previously had due to mechanical processing.
Because of the PAD and grain processing, it is possible to obtain artificial leather that has both the appearance and feel of genuine leather, both of which are essential for genuine leather.

[Brief explanation of drawings]

FIG. 1(a) is a process diagram for carrying out the method of the first invention of the present invention, FIG. 1(b) is a side view of the graining roll, and FIG. 1(c) is a side view of the surface treatment side coating roll. Side view, 2nd
The figure is a partially enlarged side view of the grain roll used in the method of the second invention of the present invention, and FIG. 3 is a process diagram for carrying out the conventional method. 1...Artificial leather 2...First layer surface treatment agent 3
... Second layer surface treatment agent 4 ... Graining roll 5 ... Roll for applying surface treatment agent 6 ... Convex portion 7 with the roughness of the graining roll... Concave portion of the graining roll! -- Cq Q) Dimension I)

Claims (1)

[Claims] 1. Apply a surface treatment agent polyamino acid urethane resin to artificial leather using a solvent that swells the artificial leather, and dry it to harden the polyamino acid urethane resin.
A method for surface treatment of artificial leather, characterized by performing graining at a temperature of 30°C and further applying a surface treatment agent. 2. Apply polyamino acid urethane resin to the artificial leather using a solvent that swells the artificial leather, and after drying, finish the concave part of the grain roll to a surface roughness of center line average roughness Ra = 10 to 70 μm, and A method for surface treatment of artificial leather, characterized in that graining is performed at 130 to 230°C using a roll whose convex portions have been roughened.