JPH05509045A - Polymer composite articles - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention relates to articles, in particular two organic polymers with different properties. The present invention relates to a sheet-like article that is a composite material made of mer. An important use of this invention is Concerning products and materials that can be easily disposed of when no longer needed.

Background of the invention By using a soluble polymer such as polyvinyl alcohol, the polymer is known to produce polymer articles designed to be disposed of by dissolution. Ru.

Polyvinyl acetate is a water-insoluble polymer obtained by polymerizing vinyl acetate. It's Rimmer. This polymer can be cured by hydrolysis or alcohol rinsing. Polyvinyl alcohol is produced by removing the acetyl group from the polymer. used for. By incompletely removing the acetyl group, vinyl alkyl Copolymers of coal and vinyl acetate can be produced. in this case, Vinyl alcohol is the main component, but vinyl acetate is still present in significant amounts Copolymers are soluble in cold water, and this type of copolymer is often "partially hydrolyzed". It is called "polyvinyl alcohol". Content of vinyl acetate component is about 11% by weight (about 12% by mole). When the above reaction is carried out almost completely, The crystallinity of polyvinyl alcohol increases and its solubility in cold water decreases significantly.

These types of polymers are "fully hydrolyzed" polyvinyl alcohol. It is called ru. In this case, the vinyl acetate content is usually 3 mol%. I can't get over it.

Polyvinyl alcohol can be formed into a film or sheet.

U.S. Pat. No. 4,444,839 (assigned by Hoechst) describes A PVA label is described that has an adhesive fixation that dissolves in cold water. Since it has a layer, it can be easily separated. This adhesive is polyvinyl Alcohol may also be used.

Hospital laundry bins made from partially hydrolyzed polyvinyl alcohol sheets It is also known to produce bags. The idea underlying this usage pattern is as follows. It is. That is, the dirty laundry is stored in this type of bag, and the entire bag is placed inside the laundry. When placed in a hospital washing machine with polyvinyl alcohol, it comes into contact with the washing water. The laundry is released into the washing water.

In practice, there is a problem that the laundry itself is wet, and such wet laundry If it comes into contact with the bag, the bag will melt and tear into pieces. polyviny Let's try to solve these problems by modifying the solubility properties of alcohol. At present, attempts have been made to do so, but they have not been successful. This kind of attempt For example, German patent application DE-A-3017246 (applicant Melchior ) The specification states that cleaning products using PVA, which is relatively insoluble and does not decompose in water other than hot water, is used as a material. A laundry bag is disclosed. To dry the bag in a low temperature wash, The bag has an auxiliary inner layer made of low-temperature melting PVA that can form a releasable weld. installed inside.

Description of the invention Generally speaking, the present invention provides for the production of water-soluble a first organic polymer, and a polymer adjacent to said polymer having the same predetermined Temperature, e.g. 20°C, slowly dissolves in water or Materials or articles containing organic polymers in a proportion that increases the blending weight ratio of the former I will provide a.

The first water-soluble organic polymer is partially hydrolyzed polyvinyl alcohol. It will be explained in more detail below that is particularly preferred. Water-insoluble organic polymers , fully hydrolyzed polyvinyl alcohol. Generally, both Both polymers have a smooth feel and are not sticky.

In one embodiment of the invention, the article or material has adjacent layers of two polymers. It is a laminate. This type of laminate is made of polymers used in industrial manufacturing processes. It may be a film or sheet. In addition, this type of laminate is made of the polymer The article may include pieces of film or sheet. The piece has one or more The shape may have a curvature in the direction.

The article or material according to the invention is characterized in that when the exposed surface of the first polymer comes into contact with water The surface will dissolve, but if the second polymer is layered, it will be protected. have sex. The second polymer prevents the first polymer from dissolving even if the protective surface gets wet act as a barrier to

In the article or material according to the invention, the two types of polymers are coextensive. The products include continuous uniform multilayer laminated films and non-woven materials. Examples include soluble polymer bodies whose surroundings are substantially covered with soluble polymers. Ru.

The second polymer is an extremely thin layer that does not remain after the first polymer has dissolved. It may be. Therefore, in this type of article, the mechanical strength is determined by the first polymer. The second polymer acts as a water-resistant barrier.

Such functionality has a wide range of applications. Generally, articles according to the invention and materials can be used when the following aspects are required. That is, first of all, The second polymer, which has a slower dissolution rate, acts as a barrier to ensure wetness. , or protect the water-soluble polymer from substances that may wet it, and then Contact the unprotected surface of the polymer with water. As a result, the dissolution of the soluble polymer is This occurs at the desired time and premature dissolution is prevented by the second polymer.

One application of the invention, described herein by way of example, is to For laundry made from water-soluble polymer films with a thin water-insoluble polymer layer It's a bag. Even if the laundry gets wet, it is very thin and insoluble. The layer acts as a barrier so that the bag does not dissolve prematurely. This wash When a bag containing laundry is placed in a hospital washing machine, the outer soluble layer of the bag is It dissolves on contact with laundry water, and the very thin insoluble layer breaks quickly, making it difficult for laundry is released into the washing water. Fragments of the insoluble layer are removed with the washing water after the washing process is completed. Discharged into the sewage system.

Complete hydrolysis is the preferred polymer, even if insoluble polymers are discharged into the sewage system Polyvinyl alcohol is biodegradable, so it won't cause any problems later on. do not have.

Another embodiment is to surround the first polymer layer, or a portion thereof, with a second polymer. The article retains its original shape in the presence of water unless it breaks or ruptures. However, the first polymer will be subjected to the action of water.

A preferred soluble polymer is partially hydrolyzed polyvinyl alcohol. As mentioned above This polymer is a copolymer of polyvinyl alcohol and vinyl acetate. It is. Generally, the degree of hydrolysis of this type of copolymer is between 75 and 95 mol%, especially It is 60 to 90 mol%. i.e. vinyl alcohol to vinyl acetate The molar ratio of is 75:25 to 95:5, more preferably 80:20 to 90:10. Ru.

Partially hydrolyzed polyvinyl alcohol is a completely biodegradable polymer. This is it The advantages brought about by this are as follows. That is, the polymer dissolves in water and is discarded. Even if the polymer is discharged into the sewage system, it is separated into ecologically acceptable substances. be understood. Therefore, in the present invention, another comonomer is used as the soluble polymer. Although this does not preclude the use of incorporated polymers, other monomers such as Polymers that do not incorporate are desirable.

The dissolution rate of the first polymer, which is more quickly solubilized, is as described below. can be varied by selecting the type of polymer and processing conditions. this The dissolution time of a polymer varies from seconds to seconds depending on the purpose of the article or material made of the polymer. It can be changed as appropriate from about 100 to several hours.

The dissolution rate of partially hydrolyzed polyvinyl alcohol increases as the molecular weight of the polymer increases. decreases somewhat. Within the range of partial hydrolysis, as the degree of hydrolysis increases, The dissolution rate of the polymer decreases. During the processing process, the polymer is subjected to heat treatment. This reduces the dissolution rate of the final processed polymer.

Typical dissolution rates for faster solubilizing polymers used in the present invention are: That's right. That is, a small amount of polymer sheet (with distilled water in contact with one side at 20'C) If touched, the sheet will fully dissolve and be destroyed within 24 hours (usually within 8 hours). However, this dissolution time can be further reduced significantly. For example, with a thickness of 50 μm The test sheet dissolves within 10 seconds.

Compared to soluble polymers of this type, polymers with relatively low solubility are more slowly dissolve. For many applications, it is desirable that the polymer exhibit some degree of insolubility. Delicious. i.e., a polymeric sheet having a thickness sufficient for handling (e.g., 50 um). Even if the sheet is immersed in sterile distilled water at 20°C, the sheet will not last for more than 8 hours or 2 hours. Retains its original shape without dissolving for more than 4 hours.

However, for certain applications, slowly dissolving soluble polymers It is possible to provide a sufficient protective barrier to polymers that dissolve more rapidly.

A preferred relatively slow-dissolving polymer is fully hydrolyzed polyvinyl alcohol. alcohol or a suitable insoluble polyvinyl alcohol copolymer. Completely hydrated The hydrolyzed freshness of decomposed PVA is 96 mol% or more, generally 98 mol% or more.

This type of polymer actually becomes somewhat water soluble at elevated temperatures, e.g. above about 50°C. It usually shows high solubility at temperatures above about 80°C (however, Certain types of polymers may not dissolve even under these elevated temperature conditions. ). However, the solubility at temperatures around room a is poor, especially when the degree of polymerization is low. High PVA has low solubility.

It is often preferred that both polymers are biodegradable; If exposed to water or natural bacteria, it will last for at most a few months. It breaks down into naturally occurring chemical species. Polyvinyl alcohol is used for both layers. This results in this result.

Articles according to the invention typically have an insoluble polymer on the outside, but a soluble polymer - may be on the outside, or a soluble polymer may be surrounded by an insoluble polymer. You may. However, the insoluble layer usually consists of an outer, more soluble polymer. only, not adhesive layers or other types of layers.

In articles or materials according to the invention, soluble relative to less soluble polymers The weight ratio of the more resistant polymer is preferably at least 2:1, more preferably (both 2:1, especially at least 5:1, especially for thick or tertiary items) In the case of original articles, the ratio can also be 10:1 to 100:1.

In another preferred embodiment, the more soluble polymer is combined with the less soluble polymer. coated with a polymer, the coating thickness generally preferably not exceeding 20μ layers. , more preferably does not exceed 10 μm, most preferably does not exceed 5 μm, and In addition, the thickness may be 2 μm or less.

For film products, the overall thickness is typically 5 μm to 1 mm, more typically Specifically, it is 10μ11 to 200μm.

Each polymer may be used in combination with other components. In particular, flexible film products In order to achieve this, it is usually desirable to incorporate a plasticizer. A suitable plasticizer is glycero trimethylolpropane and glycols. one or both layers If desired, a coloring agent and/or a filler may be added. This kind of accompaniment As additives, conventional ones may be used.

Articles according to the invention may have various forms. For example, the film It may have a two-layer structure consisting of a reamer or a less soluble polymer. It has a sandwich structure with a more soluble polymer layer interposed between the polymer layers. You can leave it there.

Non-film articles are made substantially or completely by less soluble polymers. It may have a coated soluble polymer core. Objects with this kind of structure The product exhibits water resistance, but once broken, the exposed core dissolves in water and the entire product becomes damaged. decomposes.

According to another aspect of the invention, a method of manufacturing the above-described composite article and material is provided. It will be done.

There are several methods for forming each component, for example, two types of polymer layers. are layered and bonded together as a composite article, e.g. a film or sheet. Ru. Generally, these methods include various casting/molding and extrusion methods. be caught.

Casting/molding methods for producing films or sheets include a first layer (PVA (if used, a less soluble polymer layer) is formed on a flat or shaped surface. and then forming a second layer on the surface of the first layer. These polymer layers are For example, a spraying method or a dropping method may be used. PVA is, for example, It can be applied together with water as an aqueous solution or dispersion containing especially plasticizers and thickeners. After application, the two polymer layers can be coated by evaporating the water to form. The extrusion process preferably includes a two-layer co-extrusion step. stomach Preference is given to the co-extrusion method.

This method is known for forming blown films from a single PVA polymer. This method may also be used. The conventional extrusion process for PVA film involves the use of a plasticized raw material. An aqueous solution or dispersion of a material, e.g. PVA, is surrounded by an air inlet. feeding a die having an annular extrusion orifice. plasticized The polyvinyl alcohol forms a tube when extruded through the orifice and The tube is compressed by the pressure of the air introduced through the air inlet. expands into a tube. This inflated tube has a pair of nips that block airflow. guided between the rollers.

A high pressure short screw extruder is suitable. This extruder usually has a smooth butt In addition to screws, in order to avoid overloading of the screws, which is a problem when using PVA, Equipped with a vibrating trickle feeder.

The inflation method, which is one embodiment of the present invention, includes the following steps: On the one hand, the polymer raw material, e.g. a polymer solution or dispersion, in a ready state is feeds each annular extrusion orifice disposed within the other, and Push the tube out of the orifice and apply air pressure inside the inner tube. Inflate both tubes by inflating the inner tube and the outer tube are combined to form a single tube of two polymer layers.

The extrusion equipment used in this method is a conventional PVA blown film manufacturing equipment. Similar but different in the following respects: the extrusion die of the former is a conventional single orifice. It has two annular orifices instead of a The corresponding feed screws are interlocked with the feed material feed means to each feed screw. .

The gas to be blown is suitably hot air supplied through the inlet in the internal annular slit. Ru. The heated air evaporates the water from the PVA, so the film-like bubbles dry out. For example, it passes through a nip roller at the top of the die.

Extrusion of PVA, including blown film, is a known technique and is well within the skill of the art. If you are a person, please set appropriate conditions (for example, set the die temperature to 150℃). can be selected.

The relative feed rate and concentration of polymer to the die orifice is determined by the desired thickness of the two layers. It can be adjusted as appropriate depending on the ratio.

If desired, processing aids such as defoamers and lubricants may be used.

According to a third aspect of the invention, it is suitable for producing the aforesaid bubble-blown film. A coextrusion device is provided.

Special uses for laminated articles include disposable packaging, protective layers for sanitary products, e.g. This includes glossy toilet bowl liners, etc. For such applications, one layer should be moisture resistant. sexuality is required. Articles of this type utilizing the film according to the invention can be used together with the contents. In addition, when it is poured into the flush toilet, it collapses, so the whole can be washed away, and it is clearly This provides the advantage of simplicity. Also, from the perspective of environmental issues, PVA Not only does it biodegrade into harmless CO2 and water, but it is also not known to be toxic. , does not pose any dangerous problems before chemical decomposition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described as examples with reference to the accompanying drawings.

FIG. 1 is a schematic side view of the inflation device.

FIG. 2 is a schematic top view of the device shown in FIG.

FIG. 3 is a schematic cross-sectional view of a coextrusion die installed in the apparatus shown in FIGS. 1 and 2. be.

FIG. 4 is an assembly diagram of the infant toilet bowl.

FIG. 5 is a schematic perspective view of a disposable diaper.

FIG. 6 is a schematic cross-sectional view of a two-layer film.

FIG. 7 is a schematic cross-sectional view of a three-layer laminated article.

FIG. 8 is a schematic cross-sectional view of a three-dimensional molded article.

Raw materials used In the embodiments below, both the insoluble layer and the soluble layer are made from PVA. Ta. As PVA, Hoechst AG's commercial product "Movio" is available. Mowiol J® was used. The soluble layer is rMoviol 26-88J [average viscosity measured as a 4% aqueous solution of 26 mPa-5” Using partially hydrolyzed PVAI with a molecular weight of 103,000 (degree of hydrolysis: 88 mol%) Manufactured by The insoluble layer is (DrM.

vial 20 98J (average molecular weight, viscosity and degree of hydrolysis are each 700 00°20 mPa-5” and 98.4 mol% fully hydrolyzed PVA) or (ii) rMowiol 56/98J (viscosity and degree of hydrolysis are substantially the same) fully hydrolyzed PVA) and rMo, which are 56 mPa-52 and 98 mol%, respectively. viol 28/99 J (viscosity and degree of hydrolysis are practically 28 m each) 50.50 mixture with Pa-52 and 99 mol% fully hydrolyzed PVA) Manufactured using.

In the case of the casting method, these polymers are prepared into an aqueous composition with the following blending ratio: Using PVA granules 15% by weight Glycerin (plasticizer) 5% by weight Water 801i amount% Add the PVA granules to the water and glycerin mixture and heat at 93°C for 15-20 minutes to dissolve. A liquid was prepared.

In the case of the coextrusion method, the components of the individual PVA compositions were selected according to known criteria. .

coextrusion equipment The experimental apparatus was assembled as shown in the schematic diagrams of FIGS. 1 to 3. Individual PVA group A pair of heated supply tanks (1) are provided for containing the ingredients, and these tanks are , each connected to the intake of a pair of supply screws (2) with a length of 10 cm. . Install the variable electric drive (3) and drive the feed screw at a pre-washed proportional speed. make it move.

The raw material fed by the feed screw (2) is fed into a coextrusion die that opens upward. (5) in a conventional manner toward each extrusion inlet. The die is , having concentric annular extrusion slits (10) and (11). This experimental equipment In the case of 11) has a diameter of 25Il111. The width of the outer slit (10) is 15m. the intestine, which is approximately four times the width of the inner slit (11). center of die The hole (15) opening into the This is for blowing in warm air.

Vertically above the die are a pair of A nip roller (16) is provided.

Co-extrusion method Extrudable PVA aqueous compositions can be prepared, e.g. and "Moviol 20-98J" were prepared as described above, and this These are housed separately in a heating tank (1). Soluble partially hydrolyzed rMo The tank containing the composition prepared from wiol 26-88j was It is connected to a feed screw (2) with an ejection slit (10). insoluble A tank containing a composition prepared from fully hydrolyzed rMowio120-98J The ink is inserted into the feed screw (2) with a narrow inner extrusion slit (11). Connect.

Heat the die to 150°C and pour the heated PVA composition into each feed screw (2 ), for example, by increasing the feed ratio of soluble polymer composition to insoluble polymer to 5 1 to supply to the die. At the same time, heated air is introduced from the air inlet (17). Then, by blowing through the hole (15) in the center of the die (5), the swollen A film bubble (20) is formed above the die. Insoluble inside the film bubble A thin layer of PVA is formed. Cooling air is supplied to the film bubbles above the die according to a conventional method. Spray from the outside. Emitted from separate slits (10) and (11) The two extrusion layers are separated by several steps from the die! IQ+ combines at a distance to form a composite film form.

The film foam quickly dries out and becomes non-adhesive due to the air being blown onto it. After being stretched between the nip rollers (16), folded flat and collected, the Cut into one sheet form.

rMoviol 56/98J instead of rMoviol 20/98J and rMowioL 28/99'' as raw material, and repeat the above operation. A film with a less soluble protective layer is obtained.

Molding method This method produces infant toilet liners. Convex molding surface (25X Figure 4a (see) is formed from a formed metal sort. This molded body has a central part that protrudes upward. (26) and a bottom surrounding rim (27) forming the edge of the liner. It has a form.

The insoluble PVA layer is made by applying a solution of rMowiol 20/98J to the convex outer surface of the mold. Formed by spraying on top. This solution is explained in the section “Materials used” above. Prepare as described. However, in this case, against the inclined surface of the mold (25) To improve the adhesion of the PVA layer, 10% by weight of water was added to the cellulose ether. 10% by weight of Tylose J®.

This first layer is made tacky by a drying process by blowing warm air onto it, and the rMowiol The first layer is sprayed with a relatively thick layer of 26-86J of concentrated aqueous solution onto the first layer. Form two layers. In particular, a particularly thick layer may be formed on the former rim (27). The edges of the liner are reinforced by

After drying the moisture from this second coating layer using heated air, the composite PVA liner - (30) is released from the mold (25). Suction made of cellulose-type stuffing material After placing the absorbent pad (31) on the bottom of the liner, the PVA adhesive layer (32) is applied. Annular release paper (32) formed on the flat surface of the rim and then siliconized is attached to the rim.

During use, the contents of the toilet bowl are kept for a long time by the insoluble inner layer of the liner. Retains without leaking. When discarding the contents and liner, use release paper (33 ) and attach the two pairs of rims by removing the PVA adhesive layer (32). The mounting surface is adhered to form a bag that completely hermetically encapsulates the contents. the bag When you put the entire bag into the flush toilet, the bag will tear after about 10 seconds, so flush it completely. I can leave.

As PVA, rMowiol 56/98J and rMoviol 28/99 Water resistance is improved by repeating the above process using a mixture with An article having an insoluble layer is obtained.

disposable diapers The backing sheet (40) for disposable diapers is prepared in the same manner as in the case of the liner described above. , prepared by successively spraying two different PVA layers followed by drying. do. However, in this case, a flat steel mold is used and the thickener rTylo seJ is not used. A thick soluble layer is formed on the outside of the diaper, and a thick soluble layer is formed on the inside (see Figure 5). A thin insoluble layer was formed on the upper side). For cast sheets, the more soluble layer The thickness of the layer is about Q, 1m+m, and the thickness of the less soluble layer is about 0.02mm. However, their thicknesses can be adjusted depending on the desired strength. usual The cellulose absorbent pad (41) is made of an insoluble thin layer using commercially available PVA adhesive. attach it to.

To test the resulting diaper, after pouring the aqueous liquid onto an absorbent pad, the diaper was After wrapping the diaper and leaving it for 8 hours, there was no change in the diaper and no leakage was observed. It was. When this rolled diaper was put into water, it tore within a few seconds and dispersed in the water. did.

6 to 8 schematically show cross-sections of various forms of articles according to the invention. .

Figure 6 shows a fully hydrolyzed PVA layer (50) with a thickness of 3 μm and a partially hydrolyzed PVA layer (50) with a thickness of 25 μm. A cross section of a flexible two-layer film made by laminating a water-decomposable PVA soluble layer (51). Show the face.

Figure 7 shows a cross-section of a disposable drinking cup manufactured from a three-layer laminate. the cup has a thick partially hydrolyzed PVA interlayer (61X thickness) to provide mechanical strength. approximately 0.5u+). The inner and outer surfaces of the cup are made of 5μI thick A thin layer of hydrolyzable PVA, the intermediate layer is protected from external moisture by the outer surface layer. from the liquid in the cup by an internal surface layer. This kind of cup If you wish to dispose of the intermediate layer after use, you can simply tear it apart and remove the intermediate layer. can be exposed and dissolved.

Figure 8 shows a cross section of a molded golf tee, showing the basic structure of the tee. The central core (71) forming the is partially hydrolyzed PVA. coated tee The thickness of the coating layer (70) of insoluble PVA is 5 μm. This coating layer is molded It may be formed on the surface of the soluble tea by a conventional method. This tee is ordinary Shows sufficient resistance to regular use. Also, this tee can be lost even under natural conditions. Due to wear and tear underneath, it rapidly breaks down when it comes into contact with natural moisture, causing it to scatter. There's nothing wrong with that.

Summary book A polymer that is soluble in water at 20°C and a polymer that is substantially insoluble in water at 20°C. a layer or film containing a higher amount of the former than the latter; A composite polymer article that may be. For example, layered articles are made from thicker soluble polymers. - insoluble polymer thin layer (thickness, for example, at least 20 μm) (thickness is, for example, smaller than 5 μm). both polymers is non-toxic and can be used for various household purposes, such as diaper backing sheets, etc. Polyvinyl alcohol, which is useful as a solvent, is preferred. The insoluble part has little mechanical strength. The soluble portion provides mechanical strength, while the soluble portion provides water resistance. Possible When the soluble part dissolves, the insoluble part collapses mechanically. This type of article is It may be manufactured by an extrusion method or a molding method.

mmtw Shinsukegyu , , -PCT/GB 91101237

Claims (14)

[Claims] 1. A first organic polymer that is water-soluble at 20°C and a port adjacent to the polymer. remer, the water solubility at 20° C. is substantially lower than that of the first organic polymer. a second organic polymer that is lower or less soluble in water, the amount of the former being more practical than the amount of the latter; Polymer composites containing a qualitatively greater proportion. 2. The second organic polymer forms a layer thinner than 20 μm on the first organic polymer layer. The composite material according to claim 1, comprising: 3. The second organic polymer forms a layer thinner than 5 μm on the first organic polymer layer. The composite material according to claim 2. 4. the weight ratio of the first organic polymer to the second organic polymer is at least 3:1; A composite material according to any one of claims 1 to 3. 5. 5. A composite according to claim 4, wherein the weight ratio is at least 5:1. 6. Claim 1 which is a laminate having adjacent polymer layers (50, 51; 60, 61). The composite material according to any one of (5) to (5). 7. A first organic polymer that is water-soluble at 20°C is a second organic polymer that is substantially less soluble or insoluble than one organic polymer; above, the amount of the former is substantially greater than the amount of the latter. , a method for manufacturing polymer composites. 8. The thickness of the second organic polymer layer in contact with the first organic polymer is less than 20 μm. 8. The method according to claim 7. 9. The thickness of the second organic polymer layer in contact with the first organic polymer is made thinner than 5 μm. 9. The method according to claim 8. 10. The weight ratio of the first organic polymer to the second organic polymer is at least 3:1. The method according to any one of claims 7 to 9. 11. 11. The method of claim 10, wherein the weight ratio is at least 5:1. 12. The composite is a laminate with adjacent polymer layers (50, 51:60, 61). 12. The method according to any one of claims 7 to 11. 13. 8. The method of claim 7, wherein the polymers are coextruded. 14. 14. The method according to claim 13, wherein the polymer is molded by an inflation method.