JP4410889B2 - Method for producing flexible string-like polyurethane foam - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for continuously producing a plurality of string-like articles of a flexible polyurethane foam having a circular or irregular shape.
[0002]
[Prior art]
The string-like chloroprene rubber or EPDM rubber foam is generally produced by extruding from a uniaxial rubber extruder in a horizontal manner and applying heating. These products have sufficient viscoelasticity when they are extruded from the extruder, so they have good shape retention. Even if they are simply extruded onto a conveyor belt, they retain a circular or irregular shape. Products can be manufactured. However, it is difficult to reduce the density of rubber foam. For example, a product having a density of 0.2 g / cm ³ or less is difficult to produce commercially.
[0003]
These string-like rubber foam products are extruded from a uniaxial rubber extruder, but the number of extrusions is limited to one or two.
This is because the extruded product is foamed as it is without using a mold. When extruding two or more, it is necessary to extrude products of the same thickness at the same speed. Molded. However, the main extrusion condition is limited to two, and if it is three or more, extrusion cannot be performed under the conditions of the same speed and the same thickness. From the above, the string-like rubber foam has a good performance but is very expensive and the field of use is limited.
[0004]
On the other hand, producing a flexible string-like polyurethane foam directly from a raw material in the same manner as a rubber foam cannot maintain the shape because of its extremely low viscoelasticity, and is therefore difficult to produce.
Therefore, a two-stage rubber-like method has been adopted in which raw materials are reacted in advance to synthesize a thermoplastic polyurethane polymer, and then the foamable thermoplastic urethane resin is melt-extruded into a string shape.
However, this method is expensive because it goes through a two-step process, that is, a first step of polymer synthesis and a second step of melt foaming. In addition, it is difficult to produce a product having a density of 0.2 g / cm ³ or less like rubber.
Further, since these products are thermoplastic and not thermosetting, they have a drawback that they have low heat resistance and cannot be used in a high temperature region.
[0005]
Further, even if a method of extruding using a thermoplastic urethane resin is adopted, not only a low-density product can be produced but also an open-cell polyurethane foam product cannot be produced by this method. Therefore, block-shaped or plate-shaped polyurethane foam was manufactured, this product was sliced with a slicer, and cut into a right angle using a round blade cutter or the like to manufacture a flexible polyurethane foam in a string shape. .
However, this method can produce a product having a square or rectangular cross section, but cannot produce a product having a circular or irregular cross section, and is very expensive than a rubber foam. Also, a product having a skin layer on the surface cannot be produced.
[0006]
Therefore, instead of melting and foaming directly, a plurality of low-density to high-density thermosetting open-cell structure or closed-cell structure flexible polyurethane foam is manufactured simultaneously at a low cost by a one-step method. Technology was desired.
Further, in terms of shape, there has been a demand for a technique for producing not only a quadrangular product in cross section but also a round, oval, semi-circular, and irregular flexible string-like polyurethane foam.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems, and the first problem is not to form a foam from an already polymerized thermoplastic polyurethane resin, but to form a string-like town directly from a polyurethane raw material. It is to provide a technique for continuously producing several to several tens of polyurethane foams simultaneously.
The second problem of the present invention is that a high-density product having a string-like density of 0.2 g / cm ³ or more can be produced, and a low-density flexible string-like polyurethane foam having a density of 0.2 g / cm ³ or less is provided. It is also to provide technology for industrial production continuously.
The third object of the present invention is to provide a technique for simultaneously producing a plurality of flexible string-like polyurethane foams having a string-like shape and having a self-forming skin larger than the internal density at the surface.
The fourth object of the present invention is to provide a technique for producing a flexible polyurethane foam having not only a quadrangular cross section but also a circular, elliptical, semicircular or irregular shape.
The fifth object of the present invention is to provide a technique for simultaneously producing a plurality of open-cell and closed-cell flexible string-like polyurethane foams.
[0008]
[Means for Solving the Problems]
The present gun of inventors, polyol required to produce a flexible string-like polyurethane foam, polyisocyanate, blowing agent, catalyst and crosslinking agent if necessary, a surfactant, Tou variable from required components, such as fillers When manufacturing multiple continuous string-like polyurethane foams,
1) a first step of continuously mixing the raw material components to produce a reactive polyurethane foam stock solution ;
2) a reactive polyurethane foam stock solution is mixture continuously over substantially the entire surface on a substrate having a releasing property to be moved, or the substrate parallel a plurality of string-shaped along the traveling direction of the A second step of applying in a divided manner,
3) Further , a third step of stacking a substrate having releasability from the upper surface ;
4) the reactive polyurethane foam stock solution is sandwiched by the two substrates having releasability to the third step, it is divided into parallel continuous plural along the traveling direction of the substrate, and a bag shape of The fourth step to do,
5) a fifth step of foam-curing the reactive polyurethane foam stock solution classified in the fourth step ;
6) a sixth step of demolding the foam-cured flexible string-like polyurethane foam from the substrate ;
The present invention was completed by finding a method capable of simultaneously producing a plurality of flexible string-like polyurethane foams .
[0009]
Here, the means for continuously mixing the polyurethane raw material components may be a low pressure method or a high pressure method mixer called a foaming machine used in the production of general polyurethane foam. Any device may be used as long as it has a pump facility for continuously feeding and means for mixing and discharging the components sent by the plurality of pumps with a stirrer or the like.
Next, this mixed reactive polyurethane foam undiluted solution is applied onto a base material having releasability to move, and this base material having releasability is generally called release paper or release film. For example, the surface of a kraft paper or the like is baked with a release silicone resin, or the surface of a kraft paper is integrated with a releasable methylpentane resin or the like, on the surface of a polyester film A baked release resin or the like may be used, or a glass fiber reinforced Teflon sheet may be used.
Here, the reactive polyurethane foam stock solution is applied onto the substrate having releasability, but even if it is applied over almost the entire surface of the releasable substrate, or has releasability. It may be applied by dividing a plurality of cords in parallel with the traveling direction of the substrate.
Next, a substrate having releasability is further stacked on the upper surface. The substrate having releasability on the upper surface is different even if it is the same as the substrate having releasability used on the lower surface. Also good.
[0010]
Next, the reactive polyurethane foam stock solution sandwiched by two base materials having releasability is continuously divided in parallel to the direction of travel of the base material, and this is achieved by using an upper surface and a lower surface. The object can be achieved by a method of pinching with a rotating belt, a method of applying a heat plate from the upper surface and the lower surface, and performing heat sealing and sorting. When this heat sealing method is adopted, it is of course preferable to use a thermoplastic film substrate or a substrate having a release property in which a thermoplastic resin is integrated on the paper surface. It is preferable that the base polyurethane foam solution is applied in parallel with the traveling direction and in a string shape, and the raw material is not applied to the heat seal surface.
In the case where a release resin such as silicon resin is treated on the film, it is preferable that the film surface is melted with heat and then heat-sealed. In the case of a method of sandwiching with a belt or the like, for example, it is preferable to select a film made of resin itself as a base material having releasability rather than integrating paper and resin.
However, any method may be used for the bag-like division as long as the reactive polyurethane foam stock solution is divided into a string shape, but a heat seal method is preferred.
Next, the reactive polyurethane foam undiluted solution is foam-cured in the divided bag-like material, but it may be natural foam cure, heat foam cure, or other methods.
Next, the foamed and cured flexible string-like polyurethane foam is removed, but in the method where the upper and lower belts are sandwiched between the upper and lower surfaces, the upper and lower belts are opened and the bags are continuously cut in the direction of travel. To do. Further, when manufactured by being divided by the heat sealing method, the mold can be removed by a method of opening the heat seal by heat or cutting the divided bag in the traveling direction.
[0011]
In the present invention, the reactive polyurethane foam undiluted solution is sandwiched by placing a substrate having releasability from the upper and lower surfaces into a sandwich shape. At this time, the desired flexible string-like polyurethane foam is open-celled. When it is desired, it is necessary to make an open part for releasing the foaming gas in the bag part in each section.
For example, even if these open portions are intermittently perforated on the upper surface of each divided bag, a small circular hole is intermittently inserted in the direction in which the product proceeds. Also good.
These open portions have the function of letting gas from being continuously bubbled to the outside and at the same time the function of releasing excess raw materials in order to produce a string-shaped product having a fixed shape.
In addition, when the flexible string-like polyurethane foam for this purpose is closed-celled, a cut is not necessarily required, but it may be used as a relief of extra raw materials for making a string-shaped product of a certain size and shape.
These cuts may be pre-opened in the film or in the middle of production, but if possible, it should be used as a base material having a releasability that has been opened in advance. It is preferable because a cut can be made.
[0012]
Moreover, as a method of applying the reactive polyurethane foam stock solution mixed on the substrate having releasability that continuously moves, it can be achieved by a method such as a doctor knife method, a reverse coater method, or a spray method, The present invention is not limited to this method, and any method may be used as long as it can be applied to the entire surface or in the traveling direction in a string shape. However, as a method of applying the reactive polyurethane foam stock solution in a string form on the moving releasable base material, a method of spraying a plurality of them is preferable. The jet spray method is particularly preferable.
[0013]
Any polyol can be used as the polyol used in the string-like polyurethane foam of the present invention as long as it is used in a general polyurethane foam. For example, any polyol such as polyoxyalkylene polyether polyol, polyester polyol, polydiene polyol can be used. be able to.
The polyisocyanate may be any polyisocyanate that can be used for urethane foams such as tolylene diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenylene polyisocyanate that are generally used. As the crosslinking agent or chain extender, 1.4 low-molecular-weight polyols such as 1.4 butashidiol, trimethylolpropane, butanediol, ethylene glycol, and diethylene glycol, and commonly used polyamines such as methylenebisdiphenylpolyamine and tolylenediamine can be used.
As the foaming agent, commonly used foaming agents such as water, chlorofluorocarbons, low boiling point organic solvents, CO _{2 and the} like can be used.
As the surfactant, generally used silicon surfactants such as polydimethylsiloxane-polyoxyalkylene glycol copolymer are preferable, but non-silicone surfactants can be used alone or in combination.
As the catalyst, any generally used catalyst such as tertiary acine and organometallic compounds can be used.
In the present invention, the present invention can also be a one-shot method or a prepolymer method in which a polyol and a polyisocyanate are reacted in advance.
In addition, the string-like polyurethane foam of the present invention may generally contain a urea bond or the like in addition to the urethane bond, but if it is flexible even if it contains an isocyanurate bond or the like, the scope of the present invention. include.
As the filler, those generally used such as inorganic fillers such as calcium carbonate, clay, barium sulfate, barium hydroxide, aluminum hydroxide, dioctyl phthalate, petroleum resin, asphalt, polybutene can be used.
[0014]
[Action]
In the present invention, a large number of string-like polyurethane foams are produced continuously at the same time. In general, when a large number of string-like polyurethane foams are manufactured simultaneously with existing technology, a reactive polyurethane foam stock solution is injected into a plurality of mold molds. However, it is impossible to manufacture an endless continuous long product.
The present invention is for producing a large number of string-like polyurethane foams simultaneously without using expensive molds, that is, using a base material having two mixed release reactive polyurethane foam stock solutions and upper and lower release papers. A plurality of bags are divided continuously in the direction of product production.
At the time of sorting, the sorted bags are in a thin state, but as the product progresses, the reactive polyurethane foam stock solution foams and increases in volume to form a circular bag. Furthermore, the polyurethane foam in the bag shape is cured by proceeding with heating, and becomes a product. The cured string-like polyurethane foam in the bag shape is continuously cut in the advancing direction using a cutter knife or the like, and then the mold is removed to obtain a product.
Further, when the string-like polyurethane foam is an open-cell foam, it is necessary to release a gas called health bubble from the cut on the upper surface of the base material whose upper surface is releasable.
[0015]
The effects of the present invention will be specifically described with reference to FIGS.
FIG. 1 is a plan view for explaining the manufacturing method of the present invention, and FIG. 2 is a side view of the apparatus. The raw material components necessary for the polyurethane foam are stirred and mixed in a mixer called a foaming machine, and are applied in the form of a string 6 on a base material 4 having releasability on the lower surface. A base material 5 having releasability is placed on the coated base material 4 having releasability from the upper surface via an upper surface roll 2.
Next, in order to divide into a bag shape, the releasable base material of the upper surface 5 and the lower surface 4 is thermally bonded using the heat plate 9, and the dividing line 7 is formed.
The internal reactive polyurethane foam stock solution 8 divided by the dividing line 7 gradually increases the foaming volume, and the divided string-like bag continuously becomes an oval or circular shape. At this point, a health bubble is generated to form a string-like polyurethane foam 11.
[0016]
In the present invention, when a deformed product other than an elliptical shape or a circular shape is desired, it is molded by pressing a heating mold for forming a deformed shape in the foaming process or the shape-forming reactive polyurethane foam final body 10. good.
[0017]
【Example】
Example 1
100 parts by weight of a polyol having a molecular weight of 3000 obtained by addition polymerization of propylene oxide to glycerin, 39.6 parts by weight of tolylene diisocyanate (T-80), 3.0 parts of H ₂ O, silicon surfactant L520 (manufactured by Nihon Unicar) 1 0.5 parts by weight, 0.25 part of triethylenediamine DABCO33LV (manufactured by Sankyo Air Products Co., Ltd.), 0.3 part of stannous octoate was mixed and discharged at a rate of 375 g per minute using a mixer called a foaming machine.
This reactive polyurethane foam stock solution was divided into 6 pieces through a spray-type division coater, and was dividedly applied at intervals of 33 mm on a 70-micron-thick polyethylene film running at a speed of 3 m per minute.
A polyethylene film having a thickness of 70 microns from the upper surface was placed on the polyethylene film coated on the lower surface, and heat-sealed continuously at a width of 5 mm by the heat plate 9 shown in FIG.
The sheet containing the six reactive polyurethane foam stock solutions 8 is introduced into the foaming opening at 80 ° C. and foamed and gradually becomes circular.
A sheet made of six bags is cut into a reactive polyurethane foam final body 10 from the upper surface using a perforated rotary cutter, and a gas called a health bubble is released from the cut and an open cell string is formed. A polyurethane foam 11 is formed. This product became a circular string-like polyurethane foam having a density of about 0.06 g / cm ³ and a diameter of 20 mm.
[0018]
【The invention's effect】
The present invention is to produce a plurality of string-like polyurethane foams simultaneously using two base materials having releasability.
For string-like polyurethane foams that could only be manufactured using a metal mold by this manufacturing method, long products can be manufactured continuously, and many products from low density to high density can be manufactured simultaneously. Can be manufactured at low cost without using a mold.
[Brief description of the drawings]
FIG. 1 is a plan view of equipment showing the manufacturing method of the present invention. FIG. 2 is a side view of equipment showing the manufacturing method of the present invention.
DESCRIPTION OF SYMBOLS 1 Lower surface supply roll 2 Upper surface supply roll 3 Carrier roll 4 Base material which has lower surface releasability 5 Base material which has upper surface releasability 6 String form coating reactive polyurethane foam stock solution 7 Heat seal line 8 Reactive polyurethane foam stock solution 9 Heat Plate 10 Reactive polyurethane foam final body 11 Stringed polyurethane foam

Claims (3)

In producing a flexible string-like polyurethane foam using necessary components such as a polyol, a polyisocyanate, a catalyst, a foaming agent , and , if necessary, a crosslinking agent, a surfactant, a filler,
1) a first step of continuously mixing the raw material components to produce a reactive polyurethane foam stock solution ;
2) a reactive polyurethane foam stock solution is mixture continuously over substantially the entire surface on a substrate having a releasing property to be moved, or the substrate parallel a plurality of string-shaped along the traveling direction of the A second step of applying in a divided manner,
3) Further , a third step of stacking a substrate having releasability from the upper surface ;
4) the reactive polyurethane foam stock solution is sandwiched by the two substrates having releasability to the third step, it is divided into parallel continuous plural along the traveling direction of the substrate, and a bag shape of The fourth step to do,
5) a fifth step of foam-curing the reactive polyurethane foam stock solution classified in the fourth step ;
6) a sixth step of demolding the foam-cured flexible string-like polyurethane foam from the substrate ;
A process for producing a plurality of flexible string-like polyurethane foams in succession simultaneously . Said have your Fourth step, a method of partitioning a continuous plurality of a reactive polyurethane foam stock solution, The method according to claim 1, characterized in that the heat-sealing method. Said have your Fifth step, the upper surface than the foaming gas substrate having a releasing property, as well as the production method according to claim 1 or 2, characterized in that escape foam.

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