WO2010137565A1

WO2010137565A1 - Process for production of polyglycolic acid resin molding having fine rugged pattern on the surface

Info

Publication number: WO2010137565A1
Application number: PCT/JP2010/058764
Authority: WO
Inventors: 文夫阿久津
Original assignee: 株式会社クレハ
Priority date: 2009-05-25
Filing date: 2010-05-24
Publication date: 2010-12-02
Also published as: JP5698664B2; JPWO2010137565A1

Abstract

A process for the production of a polyglycolic acid resin molding having a fine rugged pattern, which comprises: a step of disposing a mold (A) having a smooth surface and a mold (B) having an uneven surface provided with a fine rugged pattern in a manner such that the smooth surface of the mold (A) and the uneven surface of the mold (B) face each other; a step of heating a polyglycolic acid resin to 200-300°C, and thereby melting the resin; a step of heating the molds (A) and (B) to a temperature of Tc+0(°C) to Tc+80(°C) (wherein Tc is the crystallization temperature of the polyglycolic acid resin); a step of interposing the molten polyglycolic acid resin between the heated molds (A) and (B), and forming a resin layer therebetween; a step of applying a pressure of 1 to 18MPa between the molds (A) and (B), and thereby transferring the fine rugged pattern of the mold (B) to the resin layer; and a step of cooling, during the period after the initiation of cooling of the mold (B) until the point of time at which the temperature of the mold (A) lowers to Tc-40 (°C), the molds (A) and (B) in a manner that keeps the temperature of the mold (A) higher than that of the mold (B), and thereby cooling and solidifying the resin layer to which the fine rugged pattern has been transferred.

Description

Method for producing polyglycolic acid-based resin molded product having fine irregularities on the surface

The present invention relates to a method for producing a polyglycolic acid-based resin molded product having a fine uneven shape on the surface, and more specifically, by transferring a fine uneven shape on a mold surface, The present invention relates to a method for producing a glycolic acid resin molding.

Resin moldings with fine irregularities on the surface, such as microchemical chips, medical biochips, surgical materials, etc., usually use a mold with fine irregularities on the surface corresponding to the desired fine irregularities It is manufactured by press molding and transferring the fine irregularities on the mold surface to a resin molded product.

However, the resin molded product having a fine uneven shape on the surface has a problem that the contact area with the mold is large and the releasability is poor. Therefore, when manufacturing a resin molded product having fine irregularities on the surface using an acrylic resin or the like, a mold release agent is applied, and the cooling rate between the upper and lower molds when the resin molded product is cooled. A difference was provided to cause warping of the resin molded product, and the close contact area between the resin molded product and the mold in the fine uneven portion was reduced to improve the releasability. For this reason, warpage of the obtained resin molded product is unavoidable, and the degree of warpage varies depending on the uneven size, shape, and thickness of the substrate of the resin molded product even under the same cooling conditions.

Japanese Patent Laid-Open No. 2008-265001 (Patent Document 1) uses a pair of molds in which the surface of one mold is a mirror surface and the surface of the other mold has fine uneven portions. In the method of manufacturing a molded article such as an acrylic resin having fine uneven portions on the surface, the uneven shapes are maintained well by rapidly cooling the fine uneven portions at a cooling rate faster than the mirror surface. However, it is disclosed that the mold can be released quickly, easily and reliably. However, there is a problem that the internal strain remains in the molded product due to rapid cooling, and the plate-like portion of the molded product is deformed when released.

JP 2008-265001 A

The present invention has been made in view of the above-described problems of the prior art, and a polyglycolic acid resin molded product having a fine concavo-convex shape on the surface is used for the overall warpage of the molded product or the breakage of fine concavo-convex portions. Another object of the present invention is to provide a method for producing a polyglycolic acid-based resin molded product that can be produced without causing deformation.

As a result of intensive studies to achieve the above object, the present inventors have used a pair of molds including a mold A having a smooth surface and a mold B having an uneven surface having a fine uneven shape. When producing a resin molding having a fine irregular shape on the surface, a polyglycolic acid resin is used as the resin, and the temperature of the mold A is set to a predetermined period after the cooling of the mold starts. By cooling the mold so as to be higher than the temperature of the mold B, the surface of the molded product has a fine concavo-convex shape without causing the overall warpage of the molded product or the damage and deformation of the fine concavo-convex parts. The inventors have found that a glycolic acid resin molded product can be produced, and have completed the present invention.

That is, the method for producing a polyglycolic acid-based resin molded product having a fine uneven shape on the surface of the present invention,
A mold placement step of placing the mold A and the mold B so that the smooth surface of the mold A and the uneven surface having a fine uneven shape of the mold B face each other;
A resin melting step in which a polyglycolic acid-based resin or a polyglycolic acid-based resin composition is melted by heating to 200 to 300 ° C .;
The mold A and the mold _{_{B, T C +0 (℃)}} ~ T C +80 (℃) (T C is. Representing the crystallization temperature of the polyglycolic acid resin) and the mold heating step of heating the ,
A resin layer forming step of arranging a molten polyglycolic acid resin or the polyglycolic acid resin composition between the heated mold A and the mold B to form a resin layer;
Applying a pressure of 1 to 18 MPa between the mold A and the mold B to transfer the fine uneven shape of the mold B to the resin layer;
The temperature of the mold A becomes higher than the temperature of the mold B after the mold B starts cooling until the temperature of the mold A reaches T _C −40 (° C.). Cooling step of cooling the mold A and the mold B to cool and solidify the resin layer to which the fine uneven shape has been transferred,
It is a method including.

In the cooling step, it is preferable to start the cooling of the mold A within 20 seconds after the cooling of the mold B is started, and when 3 seconds or more have passed since the cooling start of the mold B, More preferably, cooling is started. In the present invention, the cooling end temperature of the mold A and the mold B is preferably T _C −40 (° C.) to T _C −100 (° C.).

In the resin melting step according to the present invention, the polyglycolic acid resin or the polyglycolic acid resin composition is preferably supplied to a cylinder of an injection molding machine heated to 200 to 300 ° C. and melted. Further, in the manufacturing method of the present invention, in the mold arranging step, the mold A is arranged on the upper side and the mold B is arranged on the lower side. In the resin forming step, the uneven surface of the mold B is arranged. It is preferable to form the resin layer on at least a fine uneven portion.

In the production method of the present invention, the reason why the overall warpage of the polyglycolic acid resin molded product having a fine uneven shape on one surface and the breakage and deformation of the fine uneven portion does not necessarily occur is not certain. The present inventors infer as follows. When manufacturing a resin molded product having a smooth surface and a concavo-convex surface having a fine concavo-convex shape, even if the mold B in contact with the concavo-convex surface of the molded product is cooled, the fine convex portions of the molded product Since the root portion is not in contact with the mold B, it is assumed that the temperature is locally higher than the other portions of the uneven surface. For this reason, when the mold A and the mold B are cooled with the same temperature history, the smooth surface is uniformly cooled in the molded product, but the uneven surface has a locally high temperature portion. Therefore, on average, it is assumed that the temperature of the uneven surface is higher than that of the smooth surface. Therefore, when a polyglycolic acid resin is used as the resin, the difference in the surface temperature causes a difference in the crystallization speed of the polyglycolic acid resin, and it is presumed that the overall warpage occurs in the molded product. The

On the other hand, in the present invention, even if there is a locally high temperature portion on the uneven surface of the molded product, the temperature of the mold A is cooled so as to be higher than the temperature of the mold B. Then, the uneven surface and the smooth surface of the molded product have the same temperature. As a result, since the polyglycolic acid resin is uniformly crystallized, it is presumed that the overall warping of the molded product does not occur.

According to the present invention, it is possible to produce a polyglycolic acid-based resin molded product having a fine uneven shape on the surface without causing an overall warp of the molded product or damage and deformation of the fine uneven portion. Become.

It is a schematic top view which shows one embodiment of the metal mold | die which has an uneven surface provided with the fine uneven | corrugated shape used for this invention. 1B is a schematic view of the mold shown in FIG. 1A taken along the line a-a ′. FIG. It is a schematic top view which shows the other embodiment of the metal mold | die which has an uneven surface provided with the fine uneven shape used for this invention. FIG. 2B is a schematic view of the mold shown in FIG. 2A taken along the line b-b ′. It is a schematic top view which shows the other embodiment of the metal mold | die which has an uneven surface provided with the fine uneven shape used for this invention. FIG. 3B is a schematic view of a c-c ′ cross section of the mold shown in FIG. 3A. 1B is a schematic top view of a polyglycolic acid-based resin molded product having a fine concavo-convex shape on the surface produced using the mold shown in FIGS. 1A and 1B. FIG. FIG. 4B is a schematic view of a d-d ′ cross section of the polyglycolic acid resin molded product shown in FIG. 4A. FIG. 4 is a schematic top view of a polyglycolic acid-based resin molded product having a fine uneven shape on the surface, produced using the mold shown in FIGS. 3A and 3B. It is the schematic of the e-e 'cross section of the polyglycolic acid type-resin molding shown in FIG. 5A. In the manufacturing method of the polyglycolic acid type resin molding of this invention, it is a schematic sectional drawing which shows one embodiment of a metal mold | die arrangement | positioning process. In the manufacturing method of the polyglycolic acid type-resin molding of this invention, it is a schematic sectional drawing which shows one embodiment of a resin layer formation process. In the manufacturing method of the polyglycolic acid type-resin molding of this invention, it is a schematic sectional drawing which shows one embodiment of a transfer process. In the manufacturing method of the polyglycolic acid type-resin molding of this invention, it is a schematic sectional drawing which shows one embodiment of a mold release process. It is a schematic sectional drawing which shows one embodiment of a pair of metal mold | die used for the manufacturing method of the polyglycolic acid type-resin molding of this invention. 4 is a graph showing temperature histories of a mold A and a mold B when the mold is cooled in Example 1. 2 is a scanning electron micrograph of the concavo-convex surface of a polyglycolic acid resin molded product to which the fine concavo-convex shape of the stamper obtained in Example 1 is transferred. 4 is a scanning electron micrograph of a concavo-convex surface of a polyglycolic acid resin molded product to which the fine concavo-convex shape of the stamper obtained in Comparative Example 1 is to be transferred.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the drawings. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

First, the polyglycolic acid resin (hereinafter referred to as “PGA resin”) used in the present invention will be described. The PGA resin used in the present invention is represented by the following formula (1):
— [O—CH ₂ —C (═O)] — (1)
A glycolic acid homopolymer consisting only of glycolic acid repeating units represented by the formula (hereinafter referred to as “PGA homopolymer”, including a ring-opened polymer of glycolide which is a bimolecular cyclic ester of glycolic acid), And a polyglycolic acid copolymer containing a glycolic acid repeating unit (hereinafter referred to as “PGA copolymer”). Such PGA-type resin may be used individually by 1 type, or may use 2 or more types together.

The comonomers used together with the glycolic acid monomer in producing the PGA copolymer include ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactides, lactones (for example, β -Propiolactone, β-butyrolactone, β-pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (eg trimethylene carbonate, etc.), ethers (For example, 1,3-dioxane, etc.), cyclic monomers such as ether esters (eg, dioxanone), amides (ε-caprolactam, etc.); lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4- Hydro, such as hydroxybutanoic acid and 6-hydroxycaproic acid Cicarboxylic acid or an alkyl ester thereof; a substantially equimolar mixture of an aliphatic diol such as ethylene glycol or 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof. Can be mentioned. These comonomers may be used individually by 1 type, or may use 2 or more types together. Of these comonomers, hydroxycarboxylic acid is preferred from the viewpoint of heat resistance.

The catalyst used when the PGA resin is produced by ring-opening polymerization of glycolide includes tin compounds such as tin halide and tin organic carboxylate; titanium compounds such as alkoxy titanate; aluminum such as alkoxyaluminum. Known ring-opening polymerization catalysts such as zirconium compounds, zirconium compounds such as zirconium acetylacetone, and antimony compounds such as antimony halide and antimony oxide.

The PGA-based resin can be produced by a conventionally known polymerization method. The polymerization temperature is preferably 120 to 300 ° C., more preferably 130 to 250 ° C., particularly preferably 140 to 220 ° C., and 150 to 200. C is most preferred. When the polymerization temperature is less than the lower limit, the polymerization tends not to proceed sufficiently. On the other hand, when the polymerization temperature exceeds the upper limit, the produced resin tends to be thermally decomposed.

The polymerization time of the PGA resin is preferably 2 minutes to 50 hours, more preferably 3 minutes to 30 hours, and particularly preferably 5 minutes to 18 hours. When the polymerization time is less than the lower limit, the polymerization does not proceed sufficiently, whereas when the upper limit is exceeded, the generated resin tends to be colored.

In the PGA resin used in the present invention, the content of the glycolic acid repeating unit represented by the formula (1) is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. 100 mass% is particularly preferable. When the content of the glycolic acid repeating unit is less than the lower limit, the crystallinity of the PGA resin tends to decrease.

The weight average molecular weight of the PGA resin is preferably 50,000 to 800,000, more preferably 80,000 to 500,000. If the weight average molecular weight of the PGA resin is less than the lower limit, the mechanical strength of the PGA resin molded product tends to decrease. On the other hand, if the upper limit is exceeded, the melt viscosity tends to increase and injection molding tends to be difficult. . The weight average molecular weight is a polymethylmethacrylate conversion value measured by gel permeation chromatography (GPC).

Further, the melt viscosity (temperature: 270 ° C., shear rate: 122 sec ⁻¹ ) of the PGA-based resin is preferably 1 to 10,000 Pa · s, more preferably 100 to 6000 Pa · s, and more preferably 300 to 4000 Pa · s. If the melt viscosity is less than the lower limit, the mechanical strength of the PGA-based resin molded product tends to decrease. On the other hand, if the melt viscosity exceeds the upper limit, injection molding tends to be difficult.

In the present invention, the PGA-based resin may be used as it is, and various additives such as a heat stabilizer, a terminal blocking agent, a plasticizer, a heat ray absorbent, an antioxidant, and other heat as necessary. You may add a plastic resin and use it as a PGA-type resin composition.

Next, the mold used in the present invention will be described. The mold used in the present invention is a pair of molds composed of a mold A having a smooth surface and a mold B having a concavo-convex surface having a fine concavo-convex shape (hereinafter also simply referred to as “concavo-convex surface”). The mold A is not particularly limited as long as it has a smooth surface, and a conventionally known one can be used, and the surface roughness of the smooth surface is not particularly limited. The mold B is not particularly limited as long as it has a fine concavo-convex shape on the surface. For example, the mold B has a fine groove 11 formed on the surface as shown in FIGS. 1A and 1B. And those having fine recesses 21 formed on the surface as shown in FIG. 2B. Further, the mold B may be formed by directly forming a fine uneven shape on the surface of the mold as shown in FIGS. 1A to 2B, or may be fine on the surface as shown in FIGS. 3A and 3B. It may be composed of a mold master 22 such as a stamper having a concavo-convex shape and a support 23 for supporting the same. Further, the region 1 having the fine concavo-convex shape may be formed at one place as shown in FIG. 1A on the concavo-convex surface of the mold B, or two or more places as shown in FIGS. 2A and 3A. It may be formed. By producing a PGA-based resin molded product using the mold B shown in FIG. 1A and FIG. 1B, the fine uneven shape on the surface of the mold B is transferred to the surface of the molded product, which is shown in FIG. 4A and FIG. 4B. A PGA-based resin molded product having fine projections 31 corresponding to the fine grooves 11 of the mold B on the surface can be obtained. Further, by producing a PGA-based resin molded product using the mold B shown in FIGS. 3A and 3B, the fine uneven shape on the mold surface is transferred to the surface of the molded product, and is shown in FIGS. 5A and 5B. A PGA-based resin molded product having fine convex portions 41 corresponding to the fine concave portions 21 of the mold B can be obtained. In the present invention, the size of the fine uneven shape is not particularly limited. However, in the present invention, the size of the convex portion and the concave portion is on the order of micrometers (for example, the diameter or width is preferably 5 to 500 μm, and high The thickness or depth is preferably 10 to 1000 μm).

Next, a method for producing a polyglycolic acid resin molded product having fine irregularities on the surface of the present invention will be described. In the present invention, first, a pair of molds including a mold A having a smooth surface as described above and a mold B having an uneven surface are prepared. And as shown to FIG. 6A, the said metal mold | die A and the said metal mold | die B are arrange | positioned so that the said smooth surface 3 and the said uneven | corrugated surface 4 may oppose (mold arrangement | positioning process). At this time, the mold A may be disposed on the upper side, the mold B may be disposed on the lower side (FIG. 6A), or the mold A may be disposed on the lower side, and the mold B may be disposed on the upper side (not shown). However, the former is preferable from the viewpoint that the fine irregularities of the mold B can be sufficiently filled with the PGA resin or PGA resin composition (hereinafter referred to as “PGA resin”). Further, the shapes of the mold A and the mold B and the fine uneven shape of the mold B are not limited to those shown in FIG. 6A.

Next, the PGA resin or the like is melted by heating to 200 to 300 ° C. (resin melting step). The heating method is not particularly limited, but for example, it is preferable to heat by supplying the PGA resin or the like to a cylinder of an injection molding machine heated to 200 to 300 ° C. When the heating temperature of the PGA resin or the like is less than the lower limit, the fluidity of the PGA resin or the like is lowered, and the PGA resin or the like tends not to be sufficiently filled in the mold, particularly fine uneven portions. In addition, when a cylinder or an extruder of an injection molding machine is used for heating and melting, the load increases, and it tends to be impossible to discharge (inject) PGA resin or the like. On the other hand, when the heating temperature exceeds the upper limit, the PGA resin tends to be colored or thermally decomposed. From such a viewpoint, the heating temperature of the PGA resin or the like is more preferably 220 to 280 ° C.

In the present invention, the mold A and the mold B, the 0 ~ 80 ° C. higher temperatures for crystallization temperature _{T C} of the PGA-based resin _{_{[T C +0 (℃) ~ T}} C +80 (℃ )] (Mold heating step). When the heating temperature of the mold is lower than the lower limit, when placing the PGA resin or the like and when applying pressure between the molds, the temperature of the PGA resin or the like decreases to increase the viscosity, and the PGA resin , Etc. tend not to be sufficiently filled into the mold, particularly fine irregularities. On the other hand, when the upper limit is exceeded, the PGA-based resin is not sufficiently crystallized and the releasability of the PGA-based resin molded product tends to decrease. From such a viewpoint, the heating temperature of the mold is more preferably T _C +30 (° C.) to T _C +60 (° C.).

The heating temperature of the mold A and the heating temperature of the mold B may be the same or different, and the heating method of the mold is not particularly limited. For example, the method of heating with a heater, the method of circulating a heating medium in a metal mold, etc. are mentioned.

Next, as shown in FIG. 6B, the molten PGA-based resin or the like is disposed between the mold A and the mold B heated to a predetermined temperature in this way to form the resin layer 5 ( Resin layer forming step). In the present invention, the mold A is disposed on the upper side, the mold B is disposed on the lower side, and the resin layer 5 is formed on at least a fine uneven portion of the uneven surface of the mold B. (FIG. 6B), the mold A may be arranged on the lower side, and the resin layer 5 may be formed on the smooth surface (not shown). The former is preferable from the viewpoint that PGA-based resin and the like can be sufficiently filled.

Although there is no restriction | limiting in particular as a formation method of the resin layer 5, For example, the molten PGA type resin etc. are discharged from discharge ports, such as a die of an injection molding machine or an extruder, on the smooth surface of the mold A, or the mold B A method of depositing on at least a fine uneven portion of the uneven surface is preferable. In the present invention, the thickness of the resin layer 5 is not particularly limited, and can be set according to the desired thickness of the molded product. In particular, according to the present invention, it is possible to suppress the overall warping of the molded product. Therefore, the present invention can produce a thin PGA-based resin molded product (for example, a thickness of 0.05 to 1.00 mm). Suitable for

Next, a pressure of 1 to 18 MPa is applied between the mold A and the mold B, and as shown in FIG. 6C, the resin layer 5 made of the PGA resin or the like is formed into a predetermined shape. The fine uneven shape of the mold B is transferred to the surface (transfer process). When the pressure applied between the molds is less than the lower limit, the filling speed of the PGA-based resin or the like to the fine irregularities of the mold B is slow, and the PGA-based resin is crystallized during the molding and is not sufficiently filled. There is a tendency that fine irregularities are deformed. On the other hand, if the upper limit is exceeded, burrs and protrusions are damaged, which tends to cause molding defects. From such a viewpoint, the pressure applied between the molds is preferably 3 to 10 MPa.

Next, the PGA-based resin layer 5 formed into a predetermined shape in this way and having a fine uneven shape on the surface is cooled and solidified by cooling the mold A and the mold B to a predetermined temperature ( Cooling step). In this case, after starting the cooling of the mold B temperature of the mold A from (the start is not included) is _T C -40 (° C.) (preferably _{T C -60 (℃)) (} T C is PGA system Until the temperature reaches the resin crystallization temperature, the mold A and the mold B are cooled so that the temperature of the mold A becomes higher than the temperature of the mold B. Thereby, the cooling balance of the whole PGA-type resin molding can be taken, and it becomes possible to reduce curvature. On the other hand, the cooling rate is increased so that the temperature of the mold A is equal to or lower than the temperature of the mold B before the temperature of the mold A reaches T _C −40 (° C.) (preferably T _C −60 (° C.)). Slightly semi-crystalline, warping occurs and mold releasability deteriorates. In addition, when the mold A and the mold B are cooled with the same temperature history during the period, an overall warpage occurs in the PGA-based resin molded product.

The method for cooling the mold is not particularly limited, but examples include a method by air cooling and a method in which a cooling pipe is provided in the mold and the cooling water is circulated therethrough. From the viewpoint of productivity, the cooling water is circulated. The cooling method is preferred.

As a specific method for cooling the mold as described above in the present invention, for example, a method of circulating cooling water having a temperature lower than that of the mold A to the mold B, and after cooling of the mold B is started. And a method for starting the cooling of the mold A.

When cooling of the mold A is started after the cooling of the mold B is started, from the viewpoint of productivity, in the present invention, the cooling of the mold B is preferably started within 30 seconds, more preferably within 20 seconds. Then, cooling of the mold A is started. Further, from the viewpoint of sufficiently preventing the occurrence of the overall warpage of the PGA-based resin molded product, preferably after 3 seconds have elapsed from the start of cooling of the mold B (that is, when 3 seconds or more have elapsed), more preferably After 5 seconds have elapsed (that is, when 5 seconds or more have elapsed), cooling of the mold A is started.

There is no particular limitation on the cooling end temperature of the mold A and the mold B, but from the viewpoint of productivity, T _C −40 (° C.) to T _C −100 (° C.) is preferable, and T _C −60 (° C.) to T _C -80 (° C) is more preferable.

In the present invention, as described above, by cooling the mold A so that the temperature of the mold A becomes higher than the temperature of the mold B in a predetermined period, it is difficult for the overall warpage to occur in the molded product, and the fine irregularities are damaged. In addition, since it is difficult for deformation to occur, transferability of fine irregularities to a PGA-based resin molding is also excellent.

After the mold is cooled in this way to cool and solidify the PGA-based resin layer 5, the pressure applied between the mold A and the mold B is released as shown in FIG. The resin-based molded product can be released (release process).

In the present invention, a PGA-based resin having excellent mold releasability is used as the resin to be molded. Therefore, the PGA-based resin molded product can be easily obtained simply by releasing the pressure between the molds as described above. Can be released. The reason why the PGA-based resin molded product is excellent in releasability is not necessarily clear, but since the PGA-based resin is a resin having high crystallinity, the volume of the PGA-based resin is easily shrunk in the mold during cooling. This is presumably because a gap is formed between the mold and the molded product.

As mentioned above, although the suitable embodiment of the manufacturing method of the polyglycolic acid-type resin molding which has the fine unevenness | corrugation shape of this invention was described, this invention is not limited to the said embodiment. For example, instead of a pair of molds consisting of a convex mold A and a concave mold B as shown in FIG. 6A, a concave mold A and a convex mold B as shown in FIG. A pair of molds may be used.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples. The crystallization temperature, molecular weight and melt viscosity were measured by the following methods.

<Crystalization temperature>
Using a press machine heated to 280 ± 2 ° C., the PGA resin was formed into a sheet having a thickness of about 200 μm. The PGA resin sheet was cooled with cold water, moisture was removed with dry air, and then immediately mounted on a differential scanning calorimeter (“DSC-15” manufactured by METTLER TOLEDO) to measure the crystallization temperature. The measurement was performed by heating the PGA resin sheet from −50 ° C. to 280 ° C. at 20 ° C./min in a nitrogen atmosphere, and then cooling from 280 ° C. to 50 ° C. at 20 ° C./min. The conversion temperature T _C (unit: ° C.) was determined.

<Melt viscosity>
About 20 g of PGA resin was introduced into a capillograph equipped with a capillary (1 mmφ, length 10 mm) [“Capillograph 1C” manufactured by Toyo Seiki Seisakusho Co., Ltd.] and held at 270 ° C. for 5 minutes. Thereafter, the melt viscosity was measured at a temperature of 270 ° C. and a shear rate of 122 sec ⁻¹ .

<Molecular weight measurement>
About 10 mg of PGA resin was dissolved in 10 mL of hexafluoroisopropanol (HFIP) solution in which 5 mM sodium trifluoroacetate was dissolved. After the obtained solution was filtered with a membrane filter made of polytetrafluoroethylene, the filtrate was gel permeation chromatography (manufactured by Showa Denko KK) using an HFIP solution in which 5 mM sodium trifluoroacetate was dissolved as an eluent. Shodex-104 ", column: HFIP-606M x 2 + pre-column connected in series, detector: RI detector), analyzed at a column temperature of 40 ° C and a flow rate of 0.6 mL / min, PGA resin The weight average molecular weight of was measured.

(Synthesis example)
A SUS container (capacity: 56 L) having a steam jacket structure equipped with a stirrer was charged with 22500 g of glycolide and 0.68 g (30 mass ppm) of tin dichloride dihydrate, and the total proton concentration in the container was 0.13. Water 1.49g was added so that it might become mol%. Note that all protons in the container include protons of moisture (humidity) in the atmosphere in the container, and the amount of water added takes into account the amount of water (0.11 g) in the atmosphere in the container. Decided. Thereafter, the container was sealed, and steam was circulated through the jacket while stirring, and the mixture was heated until the temperature of the mixture in the container reached 100 ° C. to melt the mixture to obtain a uniform liquid mixture.

Next, a reactor comprising a jacket-structured main body provided with a reaction tube (made of SUS304) having an inner diameter of 24 mm and two jacket-structured metal plates (made of SUS304) was prepared. After attaching one of the metal plates (hereinafter referred to as “lower plate”) to the lower opening of the reaction tube, the temperature of the liquid mixture is maintained at 100 ° C. from the upper opening of the reaction tube. It was transferred as it was. Immediately after the transfer, the other metal plate (hereinafter referred to as “upper plate”) was attached and the reaction tube was sealed. Thereafter, a heat medium oil at 170 ° C. was circulated through the main body and a jacket of two metal plates and held for 7 hours to synthesize a polyglycolic acid resin (PGA resin).

Next, the heat medium oil circulating in the jacket was cooled to cool the reaction apparatus to near room temperature. Thereafter, the lower plate was removed, and the PGA resin mass was taken out from the lower opening of the reaction tube. In addition, when a PGA resin is synthesized by this method, the yield is almost 100%. The obtained PGA resin block was pulverized by a pulverizer.

Crystallization temperature _{T C} of the obtained PGA resin was 140 ° C.. Further, the melt viscosity (temperature: 270 ° C., shear rate: 122 sec ⁻¹ ) of this PGA resin was 550 Pa · s, and the weight average molecular weight (in terms of polymethyl methacrylate) in GPC measurement was 225,000.
Example 1
Molding is performed using a melt fine transfer (R) system “MTM-100-15” manufactured by Nippon Steel Co., Ltd., and as a mold, there are an upper mold A having a smooth surface and a fine surface. A pair of microstructure forming molds was used, including a lower mold B (FIGS. 3A and 3B) consisting of a stamper 22 (130 mm square) having a concavo-convex shape and a support 23 supporting the stamper 22 (130 mm square). On the uneven surface of the stamper 22 having a fine uneven shape, as shown in FIG. 3A, there are 4 regions 1 (diameter 35 mm) in which a plurality of recesses 21 (diameter 10 μm × depth 30 μm) are formed with a pitch width of 20 μm. It is formed in the place. A slit die having a slit length of 100 mm was attached to the cylinder outlet of the injection molding machine.

First, as shown in FIG. 6A, the mold A is mounted on the injection molding machine as the upper mold, the mold B is mounted on the lower mold, and the smooth surface 3 and the concavo-convex surface 4 face each other. did. Next, after the cylinder (inner diameter 20 mm) of the injection molding machine was heated to 270 ° C., the PGA resin synthesized in the synthesis example was supplied to the cylinder and melted.

Further, the mold A and the mold B were heated to 190 (= T _C +50) ° C. Next, the molten PGA resin in the cylinder is applied onto the uneven surface of the stamper 22 by injection through a slit die, and the molten PGA resin layer 5 having a thickness of about 1.5 mm is applied to the stamper 22 as shown in FIG. 6B. It formed on the uneven surface. Thereafter, as shown in FIG. 6C, the mold A and the mold B are combined, a pressure of 5 MPa is applied between the molds, and held for 20 seconds, and the resin layer 5 is molded into a predetermined shape. .

Next, when the heating of the mold B was stopped, the mold B was rapidly cooled by flowing cooling water at 20 ° C. through a cooling pipe (not shown) of the mold B almost simultaneously. On the other hand, when the heating of the mold A is stopped 15 seconds after the start of the cooling of the mold B, almost 20 ° C. cooling water is allowed to flow through the cooling pipe (not shown) of the mold A at the same flow rate as the cooling water of the mold B. The mold A was cooled rapidly. Cooling of mold A and mold B was continued until the temperature of both molds was about 60 ° C. FIG. 8 shows the temperature history of the mold A and the mold B in this cooling process. Also shows the temperature of the mold A at a time when the temperature of the mold B becomes 100 ₍₌ T C -40) ℃ and 80 ₍₌ T C -60) ℃ in Table 1.

Thereafter, as shown in FIG. 6D, the pressure applied between the molds is released to release the PGA resin molded product 6, and the PGA resin molded product (100 mm × 100 mm, thickness 0) shown in FIGS. 5A and 5B is released. 0.5 mm). On one surface of the PGA resin molded product, four regions 2 (diameter 35 mm) where a plurality of convex portions 41 (diameter 10 μm × height 30 μm) are formed are formed. When the obtained PGA resin molding was visually observed, no overall warping occurred. Further, when the uneven surface having a fine uneven shape was observed with a scanning electron microscope (“JSM6301F” manufactured by JEOL Ltd.), as shown in FIG. 9, the protrusions were not damaged or deformed, and the stamper It was confirmed that 22 fine uneven shapes were transferred satisfactorily.

(Example 2)
The heating temperature of the cylinder of the injection molding machine was changed to 250 ° C., to change the heating temperature of the mold A and the mold B to _{200 (= T C +60) ℃} , applied between the mold A and the mold B The pressure was changed to 3 MPa, and a plurality of convex portions (diameter 10 μm × high) were formed on the surface in the same manner as in Example 1 except that the heating of the mold A was stopped and the cooling was started 18 seconds after the start of the cooling of the mold B. A PGA resin molded product having a thickness of 30 μm was produced. In the cooling step, it shows the temperature of the mold A at a time when the temperature of the mold B becomes 100 ₍₌ T C -40) ℃ and 80 ₍₌ T C -60) ℃ in Table 1. When the obtained PGA resin molding was visually observed, no overall warping occurred. Further, when the uneven surface having a fine uneven shape was observed with a scanning electron microscope in the same manner as in Example 1, no damage or deformation of the convex portion was observed, and the fine uneven shape of the stamper 22 was successfully transferred. It was confirmed that

(Example 3)
The heating temperature of the cylinder of the injection molding machine was changed to 290 ° C., to change the heating temperature of the mold A and the mold B to _{170 (= T C +30) ℃} , mold after 10 seconds from the start of cooling of the mold B A PGA resin molded article having a plurality of convex portions (diameter 10 μm × height 30 μm) formed on the surface was prepared in the same manner as in Example 1 except that the heating of A was stopped and the cooling was started. In the cooling step, it shows the temperature of the mold A at a time when the temperature of the mold B becomes 100 ₍₌ T C -40) ℃ and 80 ₍₌ T C -60) ℃ in Table 1. When the obtained PGA resin molding was visually observed, no overall warping occurred. Further, when the uneven surface having a fine uneven shape was observed with a scanning electron microscope in the same manner as in Example 1, no damage or deformation of the convex portion was observed, and the fine uneven shape of the stamper 22 was satisfactorily transferred. It was confirmed that

(Comparative Example 1)
A PGA resin molded product was produced in the same manner as in Example 1 except that the heating temperature of the cylinder of the injection molding machine was changed to 250 ° C. and the applied pressure between the mold A and the mold B was changed to 20 MPa. In the cooling step, it shows the temperature of the mold A at a time when the temperature of the mold B becomes 100 ₍₌ T C -40) ℃ and 80 ₍₌ T C -60) ℃ in Table 1. When the obtained PGA resin molded product was visually observed, no overall warping occurred, but the uneven surface on which the fine uneven shape of the mold B was to be transferred was scanned in the same manner as in Example 1. When observed with a scanning electron microscope, as shown in FIG. 10, the convex portion was damaged at the base, and the fine irregular shape of the stamper 22 was not transferred.

(Comparative Example 2)
An attempt was made to produce a PGA resin molding in the same manner as in Example 1 except that the heating temperature of the cylinder of the injection molding machine was changed to 190 ° C., but the melt viscosity became high and the PGA resin was coated on the stamper 22 during application. Crystallization progressed, and it was difficult to fill the recesses.

(Comparative Example 3)
The heating temperature of the mold A and the mold B was changed to _{195 (= T C +55) ℃} , change the pressure applied between the mold A and the mold B to 3 MPa, the mold A and the mold B A PGA resin molded article was produced in the same manner as in Example 1 except that heating was stopped simultaneously and cooling was started. In the cooling step, it shows the temperature of the mold A at a time when the temperature of the mold B becomes 100 ₍₌ T C -40) ℃ and 80 ₍₌ T C -60) ℃ in Table 1. When the obtained PGA resin molding was visually observed, warping occurred in the longitudinal direction of the molding, and the other end warped 10 mm toward the smooth surface with respect to one end.

As is apparent from the results shown in Table 1 and FIGS. 9 to 11, when a PGA resin molded product having fine irregularities on the surface was produced by the production method of the present invention (Examples 1 to 3), molding was performed. The overall warpage of the product and breakage and deformation of the fine protrusions did not occur, and a PGA resin molded product having a fine uneven shape could be stably produced. On the other hand, when the pair of molds was cooled with the same temperature history (Comparative Example 3), warpage occurred in the molded product itself. Further, as in the case of the present invention, even when the temperature history during the mold cooling is different between the molds, the applied pressure between the molds is larger than the range according to the present invention (Comparative Example). In 1), the fine convex part of the PGA resin molded product was damaged.

As described above, according to the present invention, a PGA-based resin molded product having a fine concavo-convex shape on the surface can be stably produced without causing an overall warp of the molded product or damage and deformation of the fine concavo-convex portion. And can be manufactured.

Therefore, since the method for producing a PGA-based resin molded product having a fine uneven shape according to the present invention is excellent in the shape stability of the molded product and the transferability of the fine uneven shape, the microchemical chip, medical biochip, surgical It is useful as a method for producing materials and the like.

1: region having a fine uneven shape on the mold surface, 2: region having a fine uneven shape on the surface of the molded product, 3: smooth surface, 4: uneven surface having a fine uneven shape, 5: resin layer, 6 : PGA-based resin molded article, 11: Fine groove on the mold surface, 21: Fine concave part on the mold surface, 22: Master mold, 23: Support, 31, 41: Fine convex part on the molded surface A: a mold having a smooth surface, B: a mold having an uneven surface having a fine uneven shape.

Claims

A mold placement step of placing the mold A and the mold B so that the smooth surface of the mold A and the uneven surface having a fine uneven shape of the mold B face each other;
A resin melting step in which a polyglycolic acid-based resin or a polyglycolic acid-based resin composition is melted by heating to 200 to 300 ° C .;
The mold A and the mold B, T C +0 (℃) ~ T C +80 (℃) (T C is. Representing the crystallization temperature of the polyglycolic acid resin) and the mold heating step of heating the ,
A resin layer forming step of arranging a molten polyglycolic acid resin or the polyglycolic acid resin composition between the heated mold A and the mold B to form a resin layer;
A transfer step of transferring a fine uneven shape of the mold B to the resin layer by applying a pressure of 1 to 18 MPa between the mold A and the mold B;
The temperature of the mold A becomes higher than the temperature of the mold B after the mold B starts cooling until the temperature of the mold A reaches T C −40 (° C.). Cooling step of cooling the mold A and the mold B to cool and solidify the resin layer to which the fine uneven shape has been transferred,
The manufacturing method of the polyglycolic acid-type resin molding which has the fine uneven | corrugated shape containing this.
The method for producing a polyglycolic acid-based resin molded article having fine irregularities according to claim 1, wherein in the cooling step, cooling of the mold A is started within 20 seconds after the cooling of the mold B is started.
3. The polyglycolic acid-based resin molded article having fine irregularities according to claim 2, wherein in the cooling step, cooling of the mold A is started when 3 seconds or more have elapsed from the start of cooling of the mold B. Production method.
4. The resin melting step, wherein the polyglycolic acid resin or the polyglycolic acid resin composition is supplied to a cylinder of an injection molding machine heated to 200 to 300 ° C. and melted. A method for producing a polyglycolic acid-based resin molded article having the fine uneven shape according to claim 1.
In the mold arrangement step, the mold A is arranged on the upper side, the mold B is arranged on the lower side,
The fine resin according to any one of claims 1 to 4, wherein, in the resin layer forming step, the resin layer is formed on at least a fine uneven portion of the uneven surface of the mold B. For producing a polyglycolic acid-based resin molded product having an uneven shape.
The cooling end temperature of the mold A and the mold B in the cooling step is T C -40 (° C) to T C -100 (° C), according to any one of claims 1 to 5. The manufacturing method of the polyglycolic acid-type resin molding which has the fine uneven | corrugated shape of description.