JP3574315B2 - Surface treatment method for cellulosic materials - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface treatment method for a cellulosic substance such as wood, paper, fiber or the like with a fluorine-containing compound for imparting water / oil repellency and stain resistance to the substance.
[0002]
[Prior art]
As a method for imparting water repellency, oil repellency, and stain resistance to cellulosic substances such as wood, paper, and fiber, treatment with a compound having a high fluorine-containing organic group has been conventionally performed. However, various effects have been devised because simply applying or impregnating does not provide a sufficient effect, and the fluorine-containing compound is detached by washing or the like so that the effect does not last long.
For example, JP-A-61-100403 and JP-A-102205 disclose that a radical generator such as benzoyl peroxide or azobisisobutyronitrile is preliminarily attached to the surface of wood, and this is used as a perfluoroalkyl group-containing acrylate. A method for imparting water repellency by treating with water is disclosed. JP-A-61-102206 discloses a method of treating wood preimpregnated with a polymer having a group capable of hydrogen bonding with a hydroxyl group in wood with a radical initiator and an acrylate containing a perfluoroalkyl group. Discloses a method of copolymerizing a monomer having a group capable of hydrogen bonding with a hydroxyl group in wood and a perfluoroalkyl group-containing acrylate in water immersed in wood.
[0003]
Further, JP-A-61-171306 discloses a method in which a mixture of a fluorine-containing monomer, an unsaturated polyester copolymerizable therewith, a radical generator, and a solvent is applied to the surface of wood, dried, and then heated to polymerize. Is disclosed.
Although these methods aim at grafting a polymer having a high fluorine-containing organic group onto the wood surface, it is not always possible to say that a sufficient amount is directly and firmly bonded to wood.
On the other hand, a method of covering the wood surface with a fluoroalkyl group by treating it with tetrafluoromethane and tetrafluoroethylene plasma has been studied (Wood Industry Vol. 44, No. 11, p. 659, 1989). Requires special equipment and gas.
[0004]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to provide a method for securely and strongly bonding a polymer having a high fluorine-containing organic group to the surface of a cellulosic material without requiring special equipment or gas.
[0005]
[Means for Solving the Problems]
As a result of various studies to achieve the above object, the present inventors have found that a copolymer containing a fluorine-containing compound having a polymerizable unsaturated bond and a specific compound as components can be used to produce a cellulose-based material such as wood, paper, or fiber. It has been discovered that the treatment allows a polymer having a high fluorine-containing organic group to be chemically bonded to the material surface, and the present invention has been completed.
That is, the present invention relates to a method for treating a cellulosic substance such as wood, paper, or fiber with a fluorine-containing compound, wherein a fluorine-containing compound having a polymerizable unsaturated bond and an isocyanate compound having a polymerizable unsaturated bond are used as components. A surface treatment method for a cellulosic substance, comprising treating the substance with a copolymer containing the same.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
The cellulosic substances targeted by the present invention include, in addition to cellulosic materials such as wood, paper, thread, cloth, and the like, products manufactured using them, such as woodwork, boxes, umbrellas, clothes, and the like. .
The isocyanate compound having a polymerizable unsaturated bond includes, for example, a C = C double bond such as 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, methacryloyl isocyanate and NCO. Diisocyanate compounds such as 2,4- or 2,6-tolylene diisocyanate, 3,3,5-trimethyl-5-isocyanatomethylcyclohexyl isocyanate, hexamethylene diisocyanate, etc. And a compound having a C ＝ C double bond and a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. Among them, 2-methacryloyloxyethyl isocyanate is most preferable from the viewpoints of reactivity, selectivity of reaction, ease of handling, availability, and the like.
[0007]
Fluorine compounds having a polymerizable unsaturated bond include (meth) acrylic acid esters of alcohols having a perfluoroalkyl group (for example, 1H, 1H, 2H, 2H-perfluorodecyl acrylate), trifluorochloroethylene / vinyl ethers ( (Meth) acrylic acid ester of a cyclohexyl vinyl ether, ethyl vinyl ether, etc.) / Hydroxybutyl (or ethyl) vinyl ether copolymer, an addition reaction product of the copolymer with the isocyanate compound having a polymerizable unsaturated bond, (Meth) acrylic acid ester of fluoropolyethylene (or propylene) glycol or an addition reaction product of the glycol with the isocyanate compound having a polymerizable unsaturated bond is included.
[0008]
As the obtained copolymer, various combinations of an isocyanate compound and a fluorine compound, and in some cases, other monomers are used. Preferred examples include, for example, 2-methacryloyloxyethyl isocyanate / 1H, 1H, 2H, including 2H- perfluorodecyl acrylate copolymer of 2-methacryloyloxyethyl isocyanate / IH, IH, 2H, a monomer component having 2H- perfluorodecyl acrylate / n-butyl acrylate copolymer terminus CF ₃ group, such as Copolymer, perfluoropolyoxyethylene (and / or propylene) diol monomethyl ether acrylate / 2-methacryloyloxyethyl isocyanate copolymer, trifluorochloroethylene / cyclohexyl vinyl ether / 4- Examples include a copolymer of an acrylic acid ester of a hydroxybutyl vinyl ether copolymer with 2-methacryloyloxyethyl isocyanate, and a copolymer containing a monomer component having a terminal CF ₃ group is particularly preferred.
[0009]
The method of copolymerizing a fluorine compound having a polymerizable unsaturated bond and an isocyanate compound having a polymerizable unsaturated bond is not limited to a special method, and various methods commonly used, such as solution polymerization and bulk polymerization, are used. , Suspension polymerization and the like are used. The method of initiating polymerization may be any of active energy rays such as ultraviolet rays, electron beams, and visible rays, peroxides, and radical initiators such as azobisisobutyronitrile.
Examples of the polymerization method include an isocyanate compound having a polymerizable unsaturated bond such as 2-methacryloyloxyethyl isocyanate, a fluorine compound having a polymerizable unsaturated bond such as 2- (perfluoroalkyl) ethyl acrylate, And optionally, a third monomer such as methyl methacryl, n-butyl acrylate, styrene or the like, as described below, is dissolved in a suitable inert solvent which does not react with the isocyanate group, and 2,2'-azobis Polymerization is carried out by adding a polymerization initiator such as isobutyronitrile and maintaining the temperature at an appropriate temperature under an atmosphere of an inert gas such as nitrogen. The addition amount of the initiator and the temperature during the polymerization are selected depending on the type of the initiator, the molecular weight of the target copolymer, and the like.
[0010]
The method of treating a cellulosic material with a copolymer containing a fluorine-containing compound having a polymerizable unsaturated bond and an isocyanate compound having a polymerizable unsaturated bond as components is not limited to one specific method. For example, a method in which a cellulose-based material is immersed in an inert solvent, and a solution of the copolymer is gradually added thereto while heating and stirring the solution, and a solution prepared by dissolving the copolymer in an inert solvent. A method of immersing a cellulosic substance or the like is preferable. At this time, when a tin compound such as dibutyltin dilaurate or tin dioctylate, or a tertiary amine such as 1,4-diazabicyclo [2.2.2] octane is used as a catalyst, a cellulose-based material and a copolymer can be obtained. The reaction is accelerated.
[0011]
The inert solvent is not particularly limited as long as it does not react with the isocyanate and does not have a polymerizable group.For example, aromatic solvents such as toluene and xylene, butyl acetate, and butyl isobutyrate can be used. And amides such as dimethylformamide and dimethylacetamide, and carbonates such as ethylene carbonate and propylene carbonate.
The treatment temperature varies depending on the type of isocyanate compound having a polymerizable unsaturated bond, but is preferably in the range of 25 ° C to 120 ° C. If the temperature is too low, the treatment takes too much time or the effect of the treatment is not sufficiently obtained. On the other hand, if the temperature is too high, undesirable effects such as deterioration of the cellulosic material are caused.
If the cellulosic material to be treated contains water, it needs to be dried beforehand because it reacts with the isocyanate. Examples of the drying method include a method by heating, a method of extracting with a solvent such as a mixture of alcohol and benzene, and the like.
The reason why the fluorine-containing compound is firmly attached to the cellulosic substance by the method of the present invention is considered to be that OH of the cellulosic substance and NCO of isocyanate are chemically bonded.
[0012]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
Synthesis Example 1
15.5 g of 2-methacryloyloxyethyl isocyanate (Karenz MOI manufactured by Showa Denko KK; abbreviated as MOI; the same applies hereinafter) as an isocyanate compound and 52 g of 1H, 1H, 2H, 2H-perfluorodecyl acrylate as a fluorine-containing compound. 0.5 g of 2,2′-azobisisobutyronitrile as a catalyst was added to a mixture of 12.8 g of n-butyl acrylate as a third component of the copolymer and 190 g of dimethylformamide as a solvent, and the mixture was stirred under a nitrogen gas atmosphere. While reacting at 70 ° C. for 3 hours, a polymer solution containing a perfluoroalkyl group and an isocyanate group was obtained.
[0013]
Comparative Synthesis Example 1
A polymerization reaction was performed in the same manner as in Synthesis Example 1 except that 11.4 g of ethyl methacrylate was used instead of the MOI to obtain a polymer solution containing a perfluoroalkyl group.
[0014]
Synthesis Example 2
1.07 mol of 1H, 1H, 2H, 2H-perfluoro-n-decanol as a fluorine-containing compound, 0.68 g of dibutyltin dilaurate and 0.2 g of 2,6-ditert-butyl-4-methylphenol as a catalyst at 90 ° C. The mixture was heated and melted, and 1.0 mol of MOI was added dropwise thereto with stirring at such a speed that the temperature in the system could be maintained at 90 ° C. After the addition, stirring was further continued at 90 ° C. for 4 hours and then cooled to room temperature, whereby a white solid melting at 57 to 58.5 ° C. was obtained.
[0015]
Synthesis Example 3
66.6 g of isophorone diisocyanate (IPDI), 0.5 g of BHT, and 100 g of cyclohexanone were charged, and after raising the temperature to 90 ° C., 39 g of 2-hydroxyethyl methacrylate was added dropwise over 2 hours. After completion of the dropwise addition, stirring was continued at the same temperature for an additional hour, and then 7.8 g of 2-hydroxyethyl methacrylate (HEMA) was added dropwise over a further 25 minutes to obtain an IPDI-HEMA adduct solution.
[0016]
Synthesis Example 4
The same polymerization reaction as in Synthesis Example 1 was carried out except that 65 g of the white solid obtained in Synthesis Example 2 was used instead of 52 g of 1H, 1H, 2H, 2H-perfluorodecyl acrylate, and a perfluoroalkyl group and an isocyanate group were used. Was obtained.
[0017]
Comparative Synthesis Example 2
Polymerization similar to that of Synthesis Example 1 except that 65 g of the white solid obtained in Synthesis Example 2 was used instead of 52 g of 1H, 1H, 2H, 2H-perfluorodecyl acrylate, and 11.4 g of ethyl methacrylate was used instead of MOI. The reaction was performed to obtain a polymer solution containing a perfluoroalkyl group.
[0018]
Synthesis Example 5
A polymer solution containing a perfluoroalkyl group and an isocyanate group was obtained in the same manner as in Synthesis 1, except that 85 g of the IPDI-HEMA adduct solution obtained in Synthesis Example 3 was used instead of 15.5 g of MOI.
[0019]
Comparative Synthesis Example 3
A polymer solution containing a perfluoroalkyl group and a hydroxyl group was obtained in the same manner as in Synthesis 1 except that 13 g of HEMA was used instead of 15.5 g of MOI.
[0020]
Example 1
A cedar board having a thickness of 2 mm was immersed in a 1: 1 mixture of ethanol and benzene (volume ratio) for 72 hours and then dried. To the polymer solution obtained in Synthesis Example 1, dibutyltin dilaurate (0.5 g) was added, and the dried cedar board was immersed in the polymer solution. After the reaction, the plate was taken out, washed by refluxing with Freon-113 for 60 hours, and dried.
When the ESCA C1s spectrum of the obtained treated cedar board was measured, peaks of 295 eV of CF ₃ group and 293 eV of CF ₂ group were recognized, indicating that the fluorine-containing group was strongly retained on the wood surface. .
[0021]
Comparative Example 1
The same treatment as in Example 1 was performed except that the polymer solution obtained in Comparative Synthesis Example 1 was used.
When the ESCA C1s spectrum of the surface of the obtained treated cedar board was measured, the peaks at 295 eV for CF ₃ groups and 293 eV for CF ₂ groups were significantly smaller than those in Example 1. This indicates that the polymer having the perfluoroalkyl group was washed away by Freon 113.
[0022]
Example 2
0.5% of 1,4-diazabicyclo [2.2.2] octane was dissolved in the polymer solution containing a perfluoroalkyl group and an isocyanate group obtained in Synthesis Example 4, and the dried Japanese paper was immersed in the solution. The reaction was performed at a temperature of 3 ° C. for 3 hours. After completion of the reaction, the mixture was reflux-washed with Freon-113 for 60 hours and dried.
The obtained Japanese paper was pasted on a wooden frame to form a mini shoji, which was sprayed with water, but showed sufficient water repellency.
[0023]
Example 3
The same processing as in Example 2 was performed, except that a cotton cloth was used instead of Japanese paper, and that the paper was not finally washed with Freon. The treated cloth thus obtained was attached to a wooden frame and sprayed with water to show water repellency. Further, the same test was performed after washing the product 30 times with a dry cleaning detergent, but the water repellency was maintained.
[0024]
Comparative Example 2
The same treatment as in Example 3 except that the polymer solution containing a perfluoroalkyl group obtained in Comparative Synthesis Example 2 was used instead of the polymer solution containing a perfluoroalkyl group and an isocyanate group obtained in Synthesis Example 4 As a result, the water repellency was almost the same as that of Example 3 immediately after the treatment, but the water repellency was hardly exhibited after washing 30 times, and the cloth became wet.
[0025]
Example 4
The same treatment as in Example 1 was performed on a cedar board except that the polymer solution obtained in Synthesis Example 5 was used instead of the polymer solution containing a perfluoroalkyl group and an isocyanate group obtained in Synthesis Example 1. Was. When the contact angle of water on the plate surface after the treatment was measured, it was 160 ° or more, and water droplets attached to the surface were almost spherical in appearance. The contact angle before the treatment with the polymer solution was 30 degrees.
[0026]
Comparative Example 3
Same as Example 4 except that the polymer solution containing a perfluoroalkyl group and a hydroxyl group obtained in Comparative Synthesis Example 3 was used instead of the polymer solution containing a perfluoroalkyl group and an isocyanate group obtained in Synthesis Example 5 Was performed on cedar boards. The contact angle of water after the treatment was 120 degrees.
[0027]
【The invention's effect】
The copolymer used in the present invention has an isocyanate group, which reacts with the hydroxyl group of the cellulosic substance and is chemically bonded, so that the copolymer is firmly held by the cellulosic substance. Since the copolymer contains a fluorine compound as a component, the copolymer has an action such as water repellency, and the action is maintained.

Claims (2)

In a method of treating a cellulosic substance such as wood, paper, or fiber with a fluorine-containing compound, a fluorine-containing compound having a polymerizable unsaturated bond and an isocyanate compound having a C = C double bond as a polymerizable unsaturated bond surface treatment of cellulosic materials, which comprises treating the material with a copolymer containing as a component. The surface treatment method for a cellulosic material according to claim 1, wherein the isocyanate compound having a C = C double bond as a polymerizable unsaturated bond is 2-methacryloyloxyethyl isocyanate.