JP2011246641A - Method for producing molded polymer article covered with fine organic fibers and molded article obtained by the production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for obtaining a structure having fine organic fibers on the surface, and to provide a structure whose surface is covered with fine organic fibers, obtained by the production method.SOLUTION: The method for producing a molded polymer article covered with fine organic fibers includes a step of bringing a molded article comprising a polymer A for forming a sea component and a polymer B for forming an island component into contact with a molded article consisting mainly of a polymer C in a prescribed temperature condition to transfer at least one portion of the polymer B to the surface of the molded article consisting mainly of the polymer C. The molded article obtained by the method is also provided.

Description

The present invention relates to a method for producing a polymer molded body coated with fine organic fibers and a molded body obtained by the production method. More specifically, the present invention relates to a method for producing a polymer molded body having polymer nanofibers on the surface and a molded body obtained by the production method.

  Regarding the production of fine organic fibers having an average diameter of nanometer order, that is, polymer nanofibers, a production method using polymer alloy spinning (for example, Patent Document 1), a production method using sea-island composite spinning (for example, Patent Document 2), A manufacturing method using electrospinning (for example, Patent Document 3) has been proposed, and in recent years, various uses have been advanced by taking advantage of the extremely large specific surface area and extremely flexible mechanical properties. .

  However, since fiber structures using polymer nanofibers are often used as non-woven fabrics, dropping off of polymer nanofibers may be a problem. In order to put the polymer nanofiber nonwoven fabric into practical use, make it a composite structure with another fabric that is not a polymer nanofiber (Patent Document 4), and perform electrospinning toward the nonwoven fabric to prevent peeling (Patent Document 5). Etc. have been made. However, in these composite forms, direct bonding cannot occur between the polymer nanofibers and other structures, and there is still a problem that durability is insufficient depending on the use environment.

  On the other hand, although not polymer nanofibers, methods for fixing carbon nanotubes to the surface of a structure are known (Patent Documents 6 and 7). Although these methods can impart electrical conductivity to the structure, carbon nanotubes, unlike organic fibers, have a very high elastic modulus, so even if they are present on the surface of the structure, an improvement effect such as surface texture can be obtained. Moreover, the modification effect resulting from polymer characteristics, such as hydrophilicity and water repellency, could not be given.

JP 2004-162244 A JP 2007-291567 A JP 2008-13864 A JP 2009-191435 A JP 2008-303521 A JP 2001-288626 A JP 2009-255568 A

  An object of the present invention is to solve the above-mentioned problems, and a manufacturing method for obtaining a structure having fine organic fibers having durability on the surface, and the surface obtained by the manufacturing method is coated with the fine organic fibers. It is to provide a structure.

The first object of the present invention is to provide a molded product containing at least a polymer A that forms a sea component and a polymer B that forms an island component under a temperature condition not lower than the melting point of the polymer A and not higher than the melting point of the polymer B. A polymer molded body coated with fine organic fibers, which comprises a step of moving at least a part of the polymer B to the surface layer of the molded body mainly composed of the polymer C by contacting the molded body mainly composed of the polymer C. This can be solved by the manufacturing method.

In that case, it can employ | adopt suitably that the average diameter of the polymer B which forms an island component is 10-1000 nm. Moreover, it is possible to suitably employ that the melting point of the polymer A is less than 200 ° C. and the melting point of the polymer B is 200 ° C. or more.
The second problem of the present invention can be solved by a polymer molded body coated with fine organic fibers obtained by any one of the above-described production methods.

  According to the method for producing a polymer molded body coated with fine organic fibers of the present invention, it is possible to easily produce a molded body in which organic fibers made of a polymer different from the polymer constituting the polymer molded body are present on the surface. And is effective for surface modification of the polymer molded body. The molded body whose surface is coated with the fine organic fibers produced in this way has excellent adhesion between the fine organic fibers and the molded body, and therefore, as a surface treatment method having excellent durability without peeling. It is valid.

Process schematic for demonstrating the manufacturing method of this invention Surface photograph of the sheet obtained in Example 1 Surface photograph of the sheet obtained in Example 3

In the production method of the present invention, a molded body containing at least a polymer A forming a sea component and a polymer B forming an island component is used. Polymer A and polymer B constitute a so-called polymer alloy state, where polymer A constitutes a sea component that is a continuous phase, and polymer B constitutes an island component.

In the case of a combination in which the polymer A and the polymer B are completely compatible, the whole may become uniform and the polymer B may not be present as an island component. On the other hand, when the compatibility between the polymer A and the polymer B is extremely poor, the average diameter of the polymer B becomes excessive, and inconvenience may occur in the subsequent steps. Therefore, the solubility parameter _SP A of the polymer A ^{(MPa 1/2)} and solubility parameter _SP B ^{(MPa 1/2)} of the polymer B is preferably the absolute value of the difference between the two is 1 to 10, 1 to 6 It is more preferable that

For example, when the polymer A is polypropylene, since the SP value of polypropylene is 16.2, the polymer B is polytetrafluoroethylene having an SP value of 12.2 (the absolute value of the difference is 4.0), or an SP value. Suitable candidates include polyethylene terephthalate having a 21.4 (absolute value of difference is 5.2), polybutylene terephthalate having an SP value of 21.6 (absolute value of difference is 5.4), and the like.
Moreover, the melting point of the polymer B needs to be higher than the melting point of the polymer A from the conditions of the subsequent heat treatment. Here, the melting point means a crystal melting temperature in a crystalline polymer, and a heat flow starting temperature in an amorphous polymer. The melting point of the polymer A is preferably less than 200 ° C. because it is easily softened by heating and has good handleability. Conversely, if the melting point of the polymer B is 200 ° C. or higher, the polymer B in the form of nanofibers is not melted, which is preferable.

  For example, when the polymer A is polypropylene, since the melting point of polypropylene is approximately 170 ° C., it is necessary to use a polymer having a melting point higher than 170 ° C. as the polymer B. Preferred examples include polyethylene terephthalate having an approximate melting point of 260 ° C., polybutylene terephthalate having a melting point of 225 ° C., polystyrene having a melting point of 230 ° C., polytetrafluoroethylene having a melting point of 320 ° C., and the like.

  The average diameter of polymer B, which is an island component present in polymer A, which is a continuous phase, is preferably 10 to 1000 nm. When the average diameter is smaller than 1000 nm, it is preferable because the transition of the polymer C described later to the surface layer is likely to proceed. On the other hand, if the average diameter is 10 nm or more, the effect due to the presence of fine organic fibers in the surface layer of the polymer C is manifested, which is preferable. The average diameter of the polymer B is more preferably 100 to 900 nm, and further preferably 200 to 800 nm. The average diameter of the polymer B is the diameter of the nanofiber measured at 50 arbitrary positions by taking a scanning electron micrograph after removing the polymer A with an organic solvent or the like that can dissolve the polymer A but does not dissolve the polymer B. It can be obtained as an average value.

In order to produce a molded body containing at least the polymer A that forms the sea component and the polymer B that forms the island component, it is first necessary to uniformly mix them by melt-kneading. Melt-kneading can be performed using an existing production apparatus such as an extruder, kneader, or static mixer. From the viewpoint of improving the dispersion of the polymer B, an extruder, particularly a biaxial extruder is preferably used. . A device having a vent part can also be used as the biaxial extruder.
Since it is necessary to employ a temperature higher than the melting point of the polymer A, the processing temperature during melt-kneading is preferably 200 ° C. or higher, and is 300 ° C. or lower from the viewpoint of suppressing thermal decomposition. Is preferred.

  The composition containing at least the polymer A and the polymer B, which are melt-kneaded, is continuously formed as it is or once cooled and solidified to be molded into pellets or powders, and then formed into a molded body by performing melt molding. Can do. The melt molding may be a film or sheet molded body by a known T-die method or inflation method, or may be a resin molded product by a known injection molding method or compression molding method. Alternatively, it may be made into a fiber structure such as a woven fabric, a knitted fabric, or a non-woven fabric after fiberizing by a known melt spinning method.

The molded body containing at least the polymer A and the polymer B can contain other constituents as long as the gist of the present invention is not impaired. For example, a heat stabilizer, an antioxidant, a colorant, a lubricant, a release agent, a plasticizer It may contain an agent, an ultraviolet absorber, inorganic particles such as silica and titanium dioxide, or may contain a different polymer other than polymer A and polymer B.
Specific examples of the polymer A include low density polyethylene, high density polyethylene, polypropylene, poly (ethylene-propylene) copolymer, polystyrene, polyvinylidene fluoride, polylactic acid, polybutylene succinate and copolymers thereof, Examples include, but are not limited to, blends and modified products.

  Specific examples of the polymer B include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyε caproamide, polyhexamethylene adipamide, polytetrafluoroethylene, polymethyl methacrylate, polyvinyl alcohol-ethylene copolymer, cellulose. Examples include, but are not limited to, acetate propionate, cellulose acetate butyrate, and copolymers, blends, and modified products thereof.

In the present invention, an operation is performed in which a molded body containing at least polymer A and polymer B is brought into contact with a molded body containing polymer C as a main component.
Here, the molded product mainly composed of polymer C is a film, sheet, plate, resin molded product, fiber structure, etc. obtained by melt molding or solution molding a composition mainly composed of polymer C. It is what. Although there is no restriction | limiting in particular about a composition, It is preferable that melting | fusing point of the polymer C is lower than melting | fusing point of the polymer B which comprises fine organic fiber. Here, the melting point means a crystal melting temperature in a crystalline polymer, and a heat flow starting temperature in an amorphous polymer. The melting point of the polymer C is preferably less than 200 ° C. because it is easily softened by heating and has good handleability. Specific examples of the polymer C include low density polyethylene, high density polyethylene, polypropylene, poly (ethylene-propylene) copolymer, polystyrene, polyvinylidene fluoride, polylactic acid, polybutylene succinate, and copolymers thereof. Examples include, but are not limited to, blends and modified products.

  The production method of the present invention includes a step of contacting a molded product containing polymer A and polymer B with a molded product containing polymer C as a main component under a temperature condition not lower than the melting point of polymer A and lower than the melting point of polymer B. It is. In this process, a very special phenomenon in which at least a part of the polymer B forming the island component contained in the polymer A forming the sea component which is a continuous phase moves to a molded body mainly composed of the polymer C. Is observed. Due to the movement of the polymer B of the island component, fine organic fibers made of the polymer B exist on the surface of the polymer C, and at least a part of the fine organic fibers made of the polymer B is intruded into the polymer C. As a result, the molded body made of the polymer C and the fine organic fibers made of the polymer B are firmly fixed (see FIG. 1).

  If the contact temperature at that time is equal to or higher than the melting point of the polymer A, the island component polymer B contained in the polymer A can move. On the contrary, if it is below the melting point of the polymer B, it is possible to maintain the form of the polymer B which is an island component in the molded body and nanofibers outside the molded body. At the same time, the contact temperature is preferably higher than the melting point of the polymer C. It is because it becomes easy for the nanofiber which consists of the polymer B to intrude into the polymer C by setting it as the melting | fusing point of the polymer C or more.

There is no particular limitation on the time for contacting the molded article containing at least the polymer A and the polymer B and the molded article containing the polymer C as a main component, but it is 3 minutes or more for the transition of the nanofibers of the polymer B. preferable. From the viewpoint of sufficient transition, it may be 5 minutes or more and 10 minutes or more. On the contrary, when the contact time is 60 minutes or less, it is possible to prevent the molded body A and the molded body C from collapsing. From the viewpoint of maintaining the body of the molded body, it is also a preferable aspect to set it to 20 minutes or less and 15 minutes or less.
There is no particular limitation on the pressure at which the molded body containing at least the polymer A and the polymer B and the molded body mainly composed of the polymer C are brought into contact with each other. However, the pressure is as low as possible to ensure the contact between the two molded bodies. It is preferable. It can also be preferably adopted that the pressure is substantially 0 MPa only by the weight of the molded body existing above. The pressure during contact is preferably 10 MPa or less, and more preferably 5 MPa or less.
As for the method of bringing a molded body containing at least the polymer A and the polymer B into contact with a molded body containing the polymer C as a main component, for example, any molded body may be a film, sheet, plate, woven fabric, knitted fabric, nonwoven fabric, etc. In the case of a fiber structure, a method may be employed in which both are stacked and heated for a predetermined time with a known hot press machine under no load or with a certain pressure applied. In addition, when a fiber structure such as a film, sheet, plate, and woven fabric, knitted fabric, and non-woven fabric can be supplied by a roll wound for a certain length, they are taken out from both rolls and laminated, and are compressed or heated by a heat roller. It may be a method in which heat treatment is continuously performed by heat treatment or the like by passing through a zone.

After contacting the molded product containing at least polymer A and polymer B with the molded product containing polymer C as a main component, the polymer C in which fine organic fibers composed of polymer B are present on the surface is obtained by peeling both of them. A molded body containing the main component can be obtained. Since the fine organic fiber made of the polymer B has a structure in which at least a part of the fine organic fiber is intruded into the polymer C, the fine organic fiber is firmly fixed and becomes a molded body functioning as a surface treatment having excellent durability.
This means that the surface of the polymer C can be highly fastened with the fine fiber polymer B. For example, when the polymer B is a polymer fiber having hydrophilicity, The surface of the molded body can be hydrophilized. Conversely, when the polymer fiber has water repellency, the surface of the molded body can be water repellent. In addition, when a large number of nanofibers are present, the same effect as when raising or flocking is obtained, and the surface texture becomes peach touch, which is also effective for modifying the texture of the molded body.

  The mechanism by which the organic microfiber made of polymer B moves and intrudes into the molded body made of polymer C by bringing the molded product made of polymer A and polymer B into contact with the molded body made of polymer C and heating is not clear. Although not present, the nanofibers of polymer B present in polymer A that has reached the melting point or higher will acquire a certain degree of mobility. When the polymer C exists in the vicinity in this state, especially when the polymer C has a higher affinity with the polymer B, which is an organic fine fiber, than the polymer A, the surface energy state is stable to move into the polymer C. Therefore, the active transition into the polymer C, that is, the penetration into the inside of the molded body made of the polymer C becomes possible, and as a result, the molding coated with the organic fine fiber having excellent wear resistance. It is thought that the body will be obtained.

  Since the molded body of the present invention has organic fine fibers on the surface, it has an effect of modifying the surface portion of the molded body due to the presence of surface fibers in addition to the original properties of the molded body. Therefore, when the molded product is a resin molded product, it can be used as a resin molded product such as a general injection molded product or an extruded molded product, a decorated industrial film, or sheet. In the case of a fiber structure, it can be used as a fiber structure for clothing having a modified surface, an industrial fiber structure, a medical fiber structure, or the like.

  Hereinafter, the present invention will be described in detail with reference to examples. Each physical property value was measured by the following method.

A. An average diameter polymer A of the polymer B and a polymer alloy molded product of the polymer B were prepared, and the polymer A was dissolved and removed using an organic solvent or an alkaline aqueous solution that can dissolve only the polymer A but not the polymer B. Then, about the sample which performed platinum-palladium vapor deposition, an electron micrograph was image | photographed using the scanning electron microscope, the diameter in the location about arbitrary 50 places of the nanofiber-like polymer B was calculated | required, and an average value was calculated | required. Average diameter.

B. Melting | fusing point The peak top temperature which shows melting | fusing of a polymer by 2nd run using DSC-7 made from Perkin Elmaer was made into melting | fusing point of a polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg.

C. MFR
Measurement of MFR as an index of the thermal fluidity of the polymer is performed in accordance with ASTM D 1238 under conditions of 230 ° C. and 2160 g load, and the weight of the polymer that has flowed in 10 minutes is measured to obtain an MFR value (g / 10 min). It was. However, when the target was polybutylene terephthalate, the load was set to 5000 g.

D. Surface state of fine fibers Using a sample obtained by depositing platinum-palladium on a molded body covered with fine organic fibers, the surface state of the molded body was observed with a scanning electron microscope. The number of fine fibers present in 100 μm square was measured at any five locations on the surface of the molded body, and the average value was obtained.

E. Using a Gakushin type flat abrasion tester for abrasion resistance fibril resistance friction fastness test, using a cotton cloth (Kanakin) as a friction cloth, the test sample was subjected to plane abrasion 500 times under a load of 500 g, and the test sample form The remaining state of the fine fibers was evaluated in three stages. “○” indicates that most of the fine fibers remain, and “△” indicates that the fine fibers remain but decrease compared to the original pre-wear sample. Fine fibers on the test sample after the wear. In the case where no residue remained, “x” was assigned, and “◯” and “△” were accepted.

[Examples 1 and 2]
As polymer A, polylactic acid having a melting point of 169 ° C. (L lactic acid ratio 98 wt%, D lactic acid ratio 2 wt%, MFR = 22 g / 10 min, hereinafter referred to as PLA 1) and polymer B having a melting point of 320 ° C. Tetrafluoroethylene (hereinafter referred to as PTFE1) was prepared.

  40 g of PLA1, which was vacuum-dried at 90 ° C. for 4 hours, 10 g of PTFE1, 0.025 g of Irganox 1010 as an antioxidant, and 0.025 g of Irgafos 168 were prepared, using a lab plast mill manufactured by Toyo Seiki Co. Kneading was carried out under conditions of a kneading temperature of 180 ° C., a blade rotation speed of 40 rpm, and a kneading time of 3 minutes to obtain a polymer alloy composition.

  The obtained polymer alloy composition was hot-pressed using a hydraulic press under the conditions of a temperature condition of 190 ° C., a pressure of 10 MPa, and a pressing time of 3 minutes, and then immediately cooled and pressed at 30 ° C. to obtain a thickness composed of PLA1 and PTFE1. A 1 mm thick polymer alloy composition sheet was obtained.

  PLA1 of this polymer alloy composition sheet was dissolved using a 4 wt% aqueous sodium hydroxide solution and observed with an electron microscope. As a result, PTFE1 was in the form of nanofibers and the diameter was found to be 720 nm on average. .

  A 1 mm thick polypropylene sheet (MFR 10 g / 10 min, melting point 165 ° C., hereinafter referred to as PP1) prepared under the conditions of a temperature condition of 190 ° C., a pressure of 10 MPa, and a pressing time of 3 minutes was prepared using a hydraulic press.

  A sheet of PP1 is laminated on the above-mentioned sheet of PLA1 and PTFE1, and annealing (heating) is performed under conditions of a temperature condition of 200 ° C., 10 minutes in Example 1, and 7 minutes in Example 2 without applying pressure. Processed. After cooling, the laminated sheets were separated into the original two sheets. The process up to this point is as schematically shown in FIG.

  When the surface of the PP1 sheet was observed with an electron microscope, a large number of fine organic fibers made of PTFE1 were randomly present in the surface layer in both Examples 1 and 2, and the ends of the fibers were partially recessed in the sheet. Structure was observed. The number of fibers per 100 μm square was 25.2 in Example 1 and 18.4 in Example 2, and it was found that many organic fine fibers existed on the surface. The PP1 sheet surface after separation obtained in Example 1 is shown in FIG.

  When the surface of the PP1 sheet after 500 times of abrasion with a cotton cloth using a Gakushin type flat abrasion tester was observed again with an electron microscope, most of the fine organic fibers made of PTFE1 on the sheet remained and resisted. The wear was found to be good.

[Examples 3 and 4]
In Example 3, polypropylene (MFR 20 g / 10 min, PP2) having a melting point of 165 ° C. was used as polymer A, PP 1 used in Example 1 was used as polymer A, and melting point 225 ° C. was used as polymer B. Polybutylene terephthalate (MFR = 26 g / 10 min, hereinafter referred to as PBT1) was prepared.

  40 g of PP2 and 10 g of PBT1 which were each vacuum-dried at 90 ° C. for 4 hours were prepared. Using a lab plast mill manufactured by Toyo Seiki Co., Ltd., kneading temperature 200 ° C., blade rotation speed 30 rpm, kneading time 3 minutes Kneading was carried out under conditions to obtain a polymer alloy composition.

  The obtained polymer alloy composition was hot-pressed using a hydraulic press under the conditions of a temperature condition of 200 ° C., a pressure of 10 MPa, and a pressing time of 3 minutes, and then immediately cooled and pressed at 30 ° C. to obtain a thickness composed of PP2 and PBT1. A 1 mm thick polymer alloy composition sheet was obtained.

  When PP1 of this polymer alloy composition sheet was dissolved in hot xylene and observed with an electron microscope, PBT1 was in the form of nanofibers, and the diameter was 850 nm on average in Example 3 and 980 nm in Example 4. I understood.

  Using a hydraulic press, a 1 mm thick polyethylene sheet (high density polyethylene, melting point 130 ° C., hereinafter referred to as HDPE1) prepared under the conditions of a temperature condition of 200 ° C., a pressure of 10 MPa, and a pressing time of 3 minutes was prepared.

  A sheet of HDPE1 is laminated on the above-mentioned sheet of PP1 and PBT1, and annealing is carried out under conditions of a temperature condition of 210 ° C., a time of 4 minutes in Example 3 and a time of 3 minutes in Example 4 without applying pressure ( (Heating) treatment was performed. After cooling, the laminated sheets were separated into the original two sheets.

  When the surface of the HDPE1 sheet was observed with an electron microscope, fine organic fibers made of PBT1 were randomly present on the surface layer, and the surface of Example 3 was shown in FIG. A partially invaginated structure was observed. In Example 3, a large number of fine fibers, 10.4 per 100 μm square, were observed on the surface, but in Example 4, the frequency was slightly less, and 5.2 per 100 μm square.

  When the surface of the PP1 sheet after 500 times of abrasion with a cotton cloth using a Gakushin type flat abrasion tester was observed again with an electron microscope, in Example 3, most of the fine organic fibers composed of PTFE1 remained on the sheet. The wear resistance was found to be good. In Example 4, a slight drop of the fine organic fiber made of PTFE1 was slightly observed after the abrasion test, but the preferred level was maintained.

[Comparative Examples 1 and 2]
In the same manner as in Example 3, a polymer alloy composition sheet made of PP2 and PBT1 having a thickness of 1 mm and a sheet made of HDPE1 were prepared.

  When these were laminated and heated, a treatment of 3 minutes was performed at 100 ° C., which is lower than the melting point of PP in Comparative Example 1, and at 260 ° C., which is higher than the melting point of PBT 1 in Comparative Example 2. In Example 1, no migration of the organic fine fibers composed of PBT1 was observed, and the surface of the HDPE sheet after the treatment remained smooth HDPE. In Comparative Example 2, the shape of the fiber made of PBT1 was lost due to melting, and a molded body apparently lacking fiber was obtained.

[Comparative Example 3]
When the polymer alloy sheet composed of PLA1 and PTFE1 obtained in Example 1 was treated with an aqueous solution of 1 wt% sodium hydroxide at 98 ° C. for 60 minutes to dissolve PLA, an organic fine fiber composed of PTFE1 was obtained. It was.
5 g of the organic fine fiber made of PTFE1 obtained, 0.8 g of water-based urethane resin (polyether urethane, pure content 25%), 0.05 g of sodium bicarbonate, and 80 g of water were poured into the pot, and the temperature was raised at 2 ° C./min. The temperature was kept for 30 minutes and the temperature was lowered to room temperature.
The obtained solution was uniformly cast into a sheet of HDPE 1 having a thickness of 1 mm obtained in the same manner as in Example 3, and evaporated to dryness at room temperature. As a result of observation with an electron microscope, it was confirmed that a large number of fine fibers of PTFE1 were present at 82.4 on the surface of the HDPE1 sheet.
When the abrasion resistance was evaluated in the same manner as in Example 1, it was found that all the fine fibers had been removed and the abrasion resistance was poor.

Claims (4)

  A molded body containing at least a polymer A that forms a sea component and a polymer B that forms an island component under a temperature condition not lower than the melting point of the polymer A and not higher than the melting point of the polymer B. A method for producing a polymer molded body coated with fine organic fibers, which comprises a step of transferring at least a part of the polymer B to the surface layer of the molded body containing the polymer C as a main component by bringing the polymer B into contact therewith. The average diameter of the polymer B which forms an island component is 10-1000 nm, The manufacturing method of the polymer molded object coat | covered with the fine organic fiber of Claim 1 characterized by the above-mentioned. The method for producing a polymer molded body coated with fine organic fibers according to claim 1 or 2, wherein the melting point of the polymer A is less than 200 ° C, and the melting point of the polymer B is 200 ° C or more.   A polymer molded article coated with fine organic fibers, obtained by the production method according to claim 1.