JPS6067127A - Preparation of water-absorbing molding material and composition thereof - Google Patents

Abstract

PURPOSE:To obtain a water-absorbing material being excellent in a swelling rate and a swelling speed, by extruding a mixture of an ethylene-vinyl acetate copolymer, resin of high water absorption and calcium stearate under specific conditions. CONSTITUTION:0-2% calcium stearate and 0-2% pigment are added to the 100pts. total of 75+ or -20pts. ethylene-vinyl acetate copolymer containing 40+ or -20% vinyl acetate and having 700% or more extensibility or resin such as acrylic rubber and natural rubber having 700% or more extensibility, and fine powder of resin of high water absorption such as starch polyacrylate having a water absorbing power of 700g/g and a particle size of 50 meshes. A material thus prepared is mixed by a mixer 1 and thereby a composition is obtained. Next, this composition is supplied to the hopper 2 of an extruder and extruded in the shape of a sheet from a die 5 of the extruder 3 provided with a continuous roll with two shafts in the rotation ratio of 1:1-1.1 or extrusion ports arranged in one transverse line at the end, under the conditions of 50- 90 deg.C and 80r.p.m. or below. Then, the composition formed in a sheet is cut by a cutting blade 7 of a continuous cutter 6, and thereby pellets 8 whose swelling rate is 80 times or more in volume and whose swelling speed gets maximum within 12hr are obtained.

Description

[Detailed explanation of the invention] The present invention is the method of manufacturing of water absorption molding H fee and its composition, and for more details, a highly stretched expansion resin, for example, ethylene vinegar bubble coales and high water absorption #. A composition containing f-fat powder as a main component is continuously pelletized while being kneaded, the resulting pellets are injection molded, and the molded product is immersed in water.
While maintaining the highest swelling rate and swelling speed, there is no elution into water or membrane failure during swelling, and after reaching the highest swelling rate, it protrudes 11x out of the water and completely returns to its original size when left alone. However, when immersed in water once, it can reach a predetermined swelling rate. This refers to water-absorbent molding (1W manufacturing method of A-thorns) and its composition, which is mainly used for toys.

Recently, water-absorbing resin molding materials have come to be used in a variety of ways, and among them, those that are publicly used for one component are elastic resins or rubbers with a high elongation rate, Water-absorbing resin powder with high water-absorbing ability is kneaded with fillers, lubricants, pigments, etc. and made into fruit granules or cut into pieces into pellets. 1 molding (the material is one variety).

Among them, molding materials with particularly high water absorption rate (swelling rate) and high-speed swelling properties are used to mold small molded products in the shape of living things, animals, and articles, and immerse them in water. do,
Toys that can expand the volume by 20 to 100 l are now in public use.

However, the construction JIIIJJ-4, which is already publicly known and publicly available,
There are many problems in materials and molded products that need to be solved. In other words, injection 1 mold (regular molding + 4 as A phase)
We have 14" of equipment for producing thorns, and in order to make them into pellets, we use a resin with a high melting point (that is, the percentage of ethylene vinegar is low), and we cut the water-absorbent resin into pellets using plasticizers and , lubricant, mold release agent, etc. are used to make pellets, so the pellets can be easily manufactured like ordinary soft PVC, and the moldability during injection molding, such as hopper drop and short mold. The swelling rate and mold releasability are excellent, but the swelling rate of the 1-shaped crystal is extremely low, and the swelling rate is 3
~Because it has 4 eyes in the center, it has not been very well received as a water-absorbing and swelling toy. Next, other publicly used varieties use ethylene-vinyl acetate copolymer with a high elongation rate (low melting point) and increase the content of water-absorbing resin to significantly increase the water absorption rate. Since the formulation is designed to increase the swelling rate and increase the swelling rate, this composition will cause stickiness, and in order to have normal moldability in the injection molding machine, it is necessary to use granules or pellets. To obtain the material of the shape,
In the manufacturing method and equipment of Gaga-type paulownia, which is commonly used,
Since this is completely impossible, instead of using a non-dehydrating material such as metal soap as a mold release agent, use a water-soluble mold release agent such as polyethylene glycol and mix it with a Henschel type mixer. Since it is made into granules, it has excellent moldability, such as hopper drop, short mold rate, and mold releasability.However, when this molded product is immersed in water, the water absorption rate is fast, but it is 50 to 80 times faster. At the stage where it swells to a volume of , the water-absorbing resin component breaks the stretched membrane of the ethylene-vinyl acetate copolymer and dissolves, causing the liquid to evaporate and the ethylene-vinyl acetate part shrinks, making it into a toy. It is no longer useful and is unpopular.

The inventor of this invention focused on such a slat, and as a result of intensive research on its manufacturing method and composition, it was discovered that a stretchable resin, such as an ethylene-vinyl acetate copolymer with a high vinyl acetate ratio, and a highly water-absorbing material with a water absorption capacity of 70017I or more were used. using a plastic resin, little or no filler, very little or no lubricant, water-insoluble metal soap, minimal amount of pigment, and almost no other additives. I haven't used it at all, and it's finally gone! J.I.
It is extruded using an M roll or an I-1 scale extruder, and while cooling it in the atmosphere, it is cut with a diode so as not to cause movement or deformation to the molecules of the crystallized composition. To obtain a method and a composition for producing a water-absorbing molded paulownia wood that satisfies all aspects such as moldability, swelling rate, swelling rate, elution property, and restorability by pelletizing the material using a cutting machine capable of producing the material. This led to the completion of the present invention.

From this point of view, if we look further at 1 and add an asterisk, we find that in order to obtain the nine conditions for good molding (A phase), it is sufficient to make pellets using existing molded paulownia manufacturing equipment. As shown in the above, materials formed from the resin's melting point have a high ratio of resin, and the elongation rate decreases in inverse proportion to the melting point of the stretchable resin, so a large amount of water-absorbing resin is used. Even if the ratio of water-absorbing resin is increased, the water-absorbing resin itself does not have a melting point, so the surface of the microparticles can remain coated with the elastic resin in a capsule shape.
1z The uncoated water-absorbing resin powder particles become exposed, and when they are immersed in water, the uncoated parts will be eluted, and there will be no effect on the swelling rate or swelling rate. , the swelling rate will reach a low level, and [
” cannot fully reach the target.

Next, contrary to the starting point of OTL, if a stretchable resin with a high elongation rate and a resin with high water absorption capacity are used, the melting point of the moderately elastic resin will be lowered, increasing its adhesiveness, and making it difficult to use normally. Under the conditions of the roll roll method and extrusion method, even if the rolls are cooled, the rotation ratio and speed of the rolls are extremely low, so the temperature of the resin rises suddenly and the resin rolls back into a sheet. However, even if the rotation ratio could be changed to form a sheet at a lower speed, it would not be possible to pelletize it using the conventional Berekida. Even if it were possible, if you look at the shape of the cut surface of the pellet, you can see that the resin that coats the surface of the grains of the water-absorbing tree in a capsule shape is stretched and partially broken. The crystallized stretchable resin undergoes a cold expansion/contraction phenomenon, so it completely separates in phase with the water-absorbent resin and remains in an amorphous form, which increases its stickiness and causes the cut surface to form between particles. (It becomes easy to wear one piece, causing a locking phenomenon in the packaging bag and the injection molding machine hopper.

For this reason, fillers such as carbonic acid, carbonate, benite, and Voigt carbon are used and kneaded in a Henschel type mixer to form a gel.
When it is initially made into granules using a molding agent such as polyethylene glycol before being soluble in water, it becomes irregularly shaped pellets that are close to spherical. This product has very good moldability during injection molding, but when it absorbs water it reaches the highest water swelling rate, the elastic resin film is destroyed, the water-absorbing resin elutes, and the elastic resin shrinks. Become lucky. This is because the added filler reduces the film strength of the stretchable resin coated in the form of microcapsules, and the film coated on the surface of the filler particles and the surface of the water-absorbing resin particles in contact with it. 11ψ covered with water absorbs water and generates /9 of tension, and 1
Since the contact point between 11* and 11* was pulled, and the membrane on the side covering the water-absorbing resin was broken, elution was significant and the maximum swelling rate was not reached, resulting in a level of 1. It is thought that the polyethylene glycol used as a mold release agent in Niji not only prevents macroscopic adhesion between pellets, but also increases the mold releasability between the fine particle surface of the water-absorbing resin 1 and the stretchable resin IKf. Furthermore, since polyethylene glycol itself reduces the film strength of the stretchable resin and is easily soluble in water, the stretchable resin film is ruptured at the same time as polyethylene glycol elutes, causing elution. These theories and clarifications were made in part by examining many combinations, and below we will show some of the 141 actual cases and explain the original January in more detail and concretely. b Example 1 Ethylene vinyl acetate copolymer (vinyl acetate ratio 40%) - 751 fls of Ultrasen UE760 manufactured by Toyo Dentatsu, I water absorbing resin (water absorption capacity 700 Da / g) 2 Sunwet IM manufactured by Sanyo Ka IJlj -800 to 100 parts, dye 0.2%/ tree 11
h), mix and disperse uniformly with a Henschel mixer, and use a 30-year single-bit extruder with a screw pinch of 39**, and the thread height of the screw on the feeder side to be 3.5 mm. , Height of thread on extrusion side 2, Q, +u
, rotation speed 6Q r/nl, tip +7.1 degrees 75°C±
1 While keeping the temperature on the ``C hopper side at 40°C ± I''C and extruding outside air #, ii a s through a die with 3 holes horizontally in a row with a thickness of 2 mm and I'lJ 3.5 NM,
17J cutter (111 Kita Iron Works 11117J cutter JrlS) whose cutting blade bites into the rubber belt and cuts it when the ladle is pushed out 2m below 17111 degrees (°C±2°C)
Then, nine consecutive cuts were made into a 3.5 am long pellet. The obtained pellets were made into 1” P S made by 6 machines.
Using mold injection molding machine, length 2Qsi,, January Oki, l,
(Using a mold that accommodates a turtle-shaped cavity and IO, the cylinder expansion temperature is 80 ± I ° CC mold temperature is 40 °
It was molded with soil ±1C. The molding defect rate (mainly short molds) was 3%, and when this molded product was immersed in water at 25°C and 40°C, it was
The maximum swelling rate in time, that is, the volume (volume x l' x thickness) was 130 times, and no elution was observed. At t, the original expansion IIη rate was reached.

Example 2 Ethylene cutting vinyl J! , 75 parts of ton combination (vinyl acetate ratio 4θ%)-cultracene UE 760, and water-absorbing tree 11Fi (l
Water absorption flt! , 700 fl/f) = "jk xt 1. M-80'0 to 1 (10 parts, calcium stearate t%/resin content, dye PIo, 1%, uniformly 1 iffl with a Henschel mixer. When the mixture was mixed and dispersed and extruded under the same conditions using the extruder of Example 1, pelletized, and processed, the molding defect rate was 2.5%.
At 40'C, L7) The Jnil IIQ'lFJ rate for water absorption is
The volume ratio is about 120 times at 25°C, and about 125 (1
'? So, the expansion ff5J speed was 25''C for about 12 hours, 4
It took about 8 hours at 0''C.I +) 1:'& IN When the water reached the river fish, no elution or minutes were observed.

Example 3゜Example 1. = The same formulation was mixed and dispersed uniformly using a Henschel mixer, and the rotation ratio of two multi-jointed rolls was set to 1:1. O
l, keep the roll temperature at 40°C ± l″C, and
4. Control the rotation speed so that the humidity of the material is 75°C ± 1°"C, feed it continuously from one end, take it out in a string shape from the other end, and feed it into the room i7 Mas°C ± 2°.
When the pellets were left to cool under C, about 27 nm was pulled out, and the same 17-part cutter as in Example 1 was used to continuously cut into pellets with a length of 3.5 mm. When the obtained pellets were injection molded under the same conditions as in Example 1, the molding defect rate was 3.5.
When this molded product was immersed in water at 25°C and 40°C, the swelling rate increased by about 130 times in volume at 25°C for about 9 hours and at 40°C for about 6 hours. This product was air-dried, and when the meat was immersed in water once, it reached its original swelling rate.

Control example 1゜The same formulation as in Example 1 was mixed uniformly in a Henschel, and the extruder for PVO was 5Q, Pitch 501111.
11 Feed side screw thread height 3.5mm, tip thread height 20mm, screw rotation 150r/
772, the temperature on the Schilling tip's 411 degrees 75±VC1 hopper side was 40 degrees C The extruded product of 2 x 3.5 pieces could not be formed into a sheet by soft peeling and sticking to the die surface.

Pair 1 original row 2 The same formulation as in Example 1 was uniformly mixed and dispersed using a Henschel mixer, and then rolled using an 18-inch PVC roll at a rotation ratio of 1:1.25 and a rotation speed of 24 r/yn. I kept the IQ'r degree at 40°C ± t"c and kneaded and tried to form a sheet, but after 2 to 3 minutes of kneading, I tried to turn it into a sheet, but it was not possible to turn it into a sheet, so I did not mix it enough. I couldn't do it, and I couldn't get the sheet out.

Bunzuki Kt Example 3] - Tylene convex 1 hot R combination (vinyl acetate rate 4o%) - Ultra Seven-nin January Bow 760 with 75 tl<, water-absorbing resin (water absorption capacity 700 g/i) - Zanque 7 10 parts of IM-800 was coated with 10 parts of white carbon and 1 part of dye, extruded using the same equipment and conditions as in Example 1, and pelletized using the same equipment. When this product was molded under the same molding conditions as Example 1♡, the molding defect rate was 3.5%.

The swelling rate of this product at 25°C and 40°C is about 60 times the volume ratio at 25°C, and about 40 times at 40°C, and the time to reach 1!4 high swelling at 25°C. It took about 8 hours and about 4 hours at 40°C, but the elution amount did not reach the maximum wet rate of 1 p.
II occurred significantly.

Comparative Example 4゜From the analysis results of Company A's product, ethylene vinyl acetate (vinyl acetate rate approximately 45%)
) approx. 100 parts, water-absorbing resin (water-absorbing capacity 10 fl/n)
The same 112. ”; As a result of molding under J conditions, the molding defect rate was 5.5%.

The water absorption 1 engraving rate of this product at 25°C and 40°C is 2
The volume ratio is about 80 times at 5°C, about 10 times at 40°C, and 2
φ reaches its maximum at 8 hours at 5°C and at 3 o'clock at 40°C;
Wakushi/71 II Exclusive-71...Koumoe; Break 1-6 hlk
+ B disaster f l' 1st part 7h A mountain shrinkable resin shrinks and completely separates.

Control example 5゜From the analysis results of 13 company products, ethylene vinyl acetate (1'il: about 30% vinyl content) about 80 parts, 1 water absorption lateral IF# (water absorption capacity about 1000 fl/II) about 100 parts, +4f time As a sharpening,
Approximately 5 parts methyl acetyl ricinolate and approximately 0.5% dye
/ Whole food composition: 1. ) Extruded using a V C extruder and using pellets that are thought to have been cut using a conventional pellet type, it is 30 times larger than Goo and about 25 times larger at 40°C, and the time to reach general commercial swelling is about 25 times larger at 25°C. It was kept at 40°C for about 20 hours for about 72 hours.

Next, an example of a preferable device for use in the production of zero-breathing-1 will be explained based on the drawings (91). FIG. 1 is a perspective view of a manufacturing device 1q using an extruder, and FIG. , is a perspective view of a manufacturing apparatus using continuous rolls.

When using the extruder shown in Figure 1,
- Charge elastic resin, water absorbent resin, and dye 1 into (1), thoroughly mix and disperse, and discharge into hopper (2) of extruder. Rotation of motor of extruder (3) and cylinder. ' Set the temperature of the paper (4), extrude it continuously from the die (5), place it on a 9J cutting machine (6) with two belt conveyors, and cut it continuously with the cutting blade (7). The length of the cutting machine and the cutting speed can be adjusted using the adjustment gear (9). When using the continuous roll shown in Fig. 2, the stretchable and water-absorbing 4'L dye is charged into the Henschel mixer (1), mixed and dispersed, and discharged into the hopper (9). The material that enters the joints of the first stage of the continuous roll is kneaded and transferred to the next stage, where it is scraped off by the terminal scraper (1), sent to the belt conveyor cutting machine (6), and cut by the cutting blade (7). ) into pellets (8).

This invention consists of the above-mentioned ': In addition to preventing pellet particles from adhering to each other and improving moldability, it is also necessary to prevent the pellet particles from adhering to each other, even if there is a problem, and to improve moldability. In addition, it is possible to easily pelletize a composition that was completely impossible to pelletize under known and publicly used production conditions without sacrificing the swelling rate or swelling rate. The moldability of the pellets is completely the same as that of the general molding product P1, and the molded product shows an unparalleled swelling rate and swelling rate, and no elution or separation occurs, so it can be used as a toy. It is also an extremely effective invention for other uses.

The above has shown the most preferred specific example of the method for producing the water-absorbing molded fruit of the present invention and its composition; however, various modifications may be made to this without departing from the spirit of the present invention.
Both of them are capable of rifling, and they also belong to the scope of the present invention.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a manufacturing device using an extruder, and Figure 2 is:
Perspective view of manufacturing equipment ff using continuous rolls (2)...Hopper, (3)-Extruder, LA), -:y If solenoid (5)...Dice, (6)...Cutting Machine, (7
)...Cutting blade, (8) Cutting object, (Part of the 9-layer adjustment gear. Patent application: Kuchiseikagaku Kogyo Co., Ltd.)

Claims (1)

[Claims] Vinyl acetate content 40±20%, or 40±5% (JI
S, -6730), elongation rate of 700 parts or more (, As
TM, D-688-72) ethylene vinyl acetate conjugate, or acrylic rubber, natural rubber, etc. with an elongation rate of 700 parts or more m 111 yen (hereinafter referred to as elastic resin) 75 ± 20
At least 50 meshes of 9% water-absorbing resin such as starch polyacrylate, cellulose polyacrylate, etc., preferably 100 meshes or more "2 Fine Powder 10
0 parts and 0 to 2% calcium stearate as a lubricant.
, preferably 0 to 0.5%, and 0 to 2% of pigment, preferably 0 to 0.5%, and after uniformly mixing in a mixer, the rotation ratio of the two machines is 1:1 to 1:■, I1 Use an extruder with a continuous roll of 1:1 to 1:1.01 or an extrusion machine with extrusion holes in a row horizontally at the tip, and set the number of revolutions to 80 or less, preferably 50 to 40, and adjust the material temperature. 50°C ~ 90°C1
Preferably, it is extruded into a sheet shape or circular or rectangular string shape while keeping the temperature at 60 to 70°C, crystallized while cooling to 40°C or less, and the cutting blade bites into the rubber belt to cut it. With a continuous cutting machine, the swelling rate of the molded product is 80 times or more in volume without destroying the crystal structure, and the swelling rate is 100 times or more in terms of volume.
A method for producing a water-absorbing molded material that reaches its maximum within 6 hours and does not cause dissolution or membrane failure, and a composition thereof.