JPH0453992B2 - - Google Patents

Description

[Detailed description of the invention] The present invention has excellent strength and extraction power, good texture,
This invention relates to a synthetic paper for coffee or tea bags that has filterability. Recently, the demand for non-woven fabrics has been increasing rapidly, and the development of applications for thin fabrics, especially for disposable fabrics, has been active. Cellulose fibers have been mainly used as materials for these non-woven fabrics, but recently, wet-laid non-woven fabrics (hereinafter referred to as synthetic paper) using synthetic fibers, dry-laid non-woven fabrics using cards or random wavers, and continuous fibers after melt spinning have been used. The technology of the spunbond method for making non-woven fabrics has gradually developed, and the amount of non-woven fabrics made from synthetic fibers is increasing year by year. Synthetic fibers used include polyester, nylon,
Among these fibers are acrylic, polypropylene, vinylon, etc., polyester fibers are used in the largest amount because they are superior in terms of cost and performance and are versatile and can be used for all kinds of purposes. In addition, as a nonwoven fabric manufacturing method, the production speed is 100%.
The production of synthetic paper is gradually increasing because the wet-type nonwoven fabric production method, which can significantly increase the production speed to more than m/min, is cost-effective. However, when making synthetic paper, it is necessary to make a synthetic paper that suits the purpose of use, and there are very few examples of it being successfully used for coffee or tea bags, and the current situation is that the excellent performance of polyester fibers is not being utilized. It is.
As a result of intensive study on synthetic paper for coffee or tea bags that mainly uses polyester fibers, the inventor of the present invention found that the composition of the three components of polyester fibers, binder fibers, and cellulose fibers that make up the synthetic paper is extremely important. That is, regarding the blending ratio of polyester fiber, binder fiber, and cellulose fiber, the blending ratio of polyester fiber is 20 to 65% by weight, and the binder fiber is 10% by weight.
~60% by weight, and the blending ratio of cellulose fibers is 5% by weight.
The present inventors have discovered that a synthetic paper having excellent strength, extraction power, good texture, and filterability for use in coffee or tea bags can be obtained by increasing the content to 50% by weight. That is, the present invention consists of polyester fibers, low melting point polyethylene terephthalate composite binder fibers, and cellulose fibers, and the polyester fibers are 20 to 65% by weight and the binder fibers are 10 to 60% by weight.
Synthetic paper for coffee or tea bags with a basis weight of 10 to 40 g/m ² containing 5 to 50 weight % of cellulose fibers with a weight % and a beating degree of 100 to 400, [herein, the beating degree (unit: ml)] is the value measured using the 2.1 Canadian standard method of the pulp freeness test method specified in JIS P8121. ] is the gist. The polyester used in the present invention is preferably polyethylene terephthalate or a copolyester mainly composed of polyethylene terephthalate, and specific examples of the copolymer component include P-oxybenzoic acid, isophthalic acid,
Examples include adipic acid, 1,4-butanediol, diethylene glycol, and the like. It goes without saying that additives such as matting agents and antistatic agents may be added to these polyesters. The polyester fiber used in the present invention is
0.5d to 6.0d is used, and the blending ratio must be 20 to 65% by weight. If the blending ratio exceeds 65% by weight, the wet strength in paper mills will be weakened,
The transfer to felt is poor, the finished product has a lot of fluff, and the texture of the synthetic paper is also poor. Furthermore, the strength and filterability of the synthetic paper are also reduced, which is not preferable. The preferred blending ratio is 20 to 65% by weight. The polyester fiber may or may not be crimped. The binder fiber used in the present invention contains polyethylene terephthalate with a copolymer component of 10 to 50%.
It is a low melting point polyethylene terephthalate composite synthetic fiber obtained by molar copolymerization, and those having a melting point in the range of 80 to 220°C are preferably used. In addition, this binder fiber is a composite fiber in which the low melting point component occupies at least a part of the single fiber surface, and may be a sheath-core type in which the low melting point component is used in the sheath part and the normal melting point component is used in the core part, or it may be a side-by-side fiber. It may be a type.
By using this binder fiber, the strength of the synthetic paper is improved when the fibers are thermally bonded. The blending ratio of binder fibers is preferably 10 to 60% by weight. If the blending ratio is less than 10% by weight, the fluff and texture of the synthetic paper will deteriorate, and the strength and filtration properties will become weaker, making it difficult to withstand use in hot water. There may be no.
Also, if the blending ratio exceeds 60% by weight, the texture will be poor, making it unsuitable for use in coffee or tea bags. The blending ratio is preferably 10 to 60% by weight. The cellulosic fibers used in the present invention are preferably natural fibers such as wood pulp or hemp, and their blending ratio should be 5 to 50% by weight. These natural fibers become fibrillated by beating,
It becomes a thin fibrous material with a network structure. This cellulose fiber has a freeness of 100 to 400, which is measured using a Canadian freeness tester in accordance with the 2.1 Canadian standard form of the pulp freeness test method specified in JIS P8121. If it is outside this range and exceeds 400, the fibrillation of the fibers will not be sufficient and small particles of coffee or tea will come out into the liquid from the gaps between the fibers of the synthetic paper, so the role of filtration with the synthetic paper will be reduced. not fulfill the purpose. Further, if the beating degree is less than 100, fibrillation of the fibers will proceed too much, slowing down the speed of liquid flowing into and out of the bag, which is undesirable as it will impair extraction. It can be said that a blending ratio of cellulose fibers of 5 to 50% by weight is excellent in extraction power, texture, filterability, etc. Furthermore, if the blending ratio of cellulose fibers exceeds 50% by weight, the odor and taste of cellulose will be mixed into the coffee or tea, which is undesirable. If the blending ratio of cellulose fibers is less than 5% by weight, small particles of coffee or tea will come out into the liquid, which is not preferable. The basis weight of the synthetic paper of the present invention is preferably 10 to 40 g/m ² . If it is less than 10 g/m ² , the water permeability is too good and it does not function as a filter, and the small particles of coffee or tea contained in the bag are It is undesirable because it comes out into the external liquid. In addition, the strength of the synthetic paper becomes weak and it cannot be put to practical use. On the other hand, if the basis weight exceeds 40 g/m ² , the filterability is too good and the extract from the contents of the bag is difficult to come out of the bag. The synthetic paper obtained by the present invention has excellent strength, extraction power, good texture, and filterability, and since it uses binder fibers, it can be easily heat-sealed. The process of making coffee or tea bags is easy. Due to these characteristics, the synthetic paper of the present invention is suitable for use in coffee or tea bags. In addition, since it uses polyester fiber, it falls within the various standard values stipulated by the Food Sanitation Act.
It can be said to be a safe synthetic paper. The present invention will be explained in more detail with reference to Examples below. In the Examples, the methods for measuring the melting point, strength, absorbance of the extract, and amount of powder contained in the extract are as follows. Furthermore, in the evaluation of performance in the examples, ◯ indicates good, △ indicates slightly poor, and × indicates poor. (1) Melting point: Using a PerkinElmer melting point meter, place 10 mg of the sample in an aluminum container at 20℃/
Measured under rising temperature conditions of min. (2) Strength: This is based on the JIS P8113 tensile strength measurement method, using a constant speed extension type tensile tester. Measured with a sample width of 25.0±0.1mm and length of 180±2mm. (3) Absorbance of the extract... Wavelength determined by Hitachi spectrophotometer
Measured using 500mμ. Place the bag in 150 c.c. of boiling water, immerse and shake for 3 minutes, and remove this solution.
Filter through a 3G glass filter and dilute the filtrate 10 times before use. (4) Amount of powder contained in the extract...extract 150c.c.
Filter through a 3G glass filter, dry in a dryer at 105℃ for 60 minutes, and weigh the filtrate. (5) Freeness: Among the pulp freeness test methods specified in JIS P8121, it is measured using a Canadian freeness tester according to 2.1 Canadian Standard Form. The pulp concentration is approximately 0.3% of the absolute dry weight, and the drainage volume (unit: ml) is accurately measured to meet the above JIS P8121.
0.3%, 20℃ according to Appendix Tables 1 and 2 listed in
Find the amount of wastewater corrected to the standard concentration and temperature. This amount of drainage is defined as freeness, which is expressed in ml as the degree of freeness. The smaller this number is, the more advanced the beating is. Examples 1 to 12 and Comparative Examples 1 to 6 Stretching ratio of 500,000 denier undrawn yarn tow of polyethylene terephthalate with intrinsic viscosity [η] = 0.65
It was stretched 3.4 times at a stretching speed of 100 m/min, and cut to 1.4 d into 5 mm pieces using a cutter. In addition, a sheath-core type [composite ratio (weight ratio)] is used, in which the sheath part is a copolymerized polyester having an intrinsic viscosity [η] = 0.62, which is obtained by copolymerizing polyethylene terephthalate with 50 moles of isophthalic acid component as a third component, and the core part is the polyethylene terephthalate. Sheath/core = 1/1] composite binder fiber 50
An undrawn yarn tow of 1,000,000 denier was drawn at a drawing ratio of 3.7 times and a drawing speed of 100 m/min, and was cut into 5 mm pieces using a cutter to obtain a binder fiber. Softwood pulp (abbreviated as NP) as cellulose fiber
The material was beaten until the degree of freeness was 360 as measured using a Canadian freeness tester. In addition,
The melting point of the sheath part of the above copolymerized polyester composite binder fiber (product name "Meltei") is 110
It was warm at ℃. The blending ratio of these three types of raw materials was variously changed as shown in the "Fiber blending ratio" column of Table 1, and these raw materials were dispersed in water using a Hoyt type beater, so that the fiber concentration was 1.0% by weight. After adjusting as described above, each of these blended liquids was supplied to a cylinder paper machine and paper was made at a paper making speed of 25 m/min. At this time, to improve dispersion, use polyacrylamide.
A 500 ppm solution was supplied to the wet section of the cylinder paper machine to give a concentration of 5 ppm. Yankee dryer temperature
The temperature was set at 140°C, and the dry heat-treated synthetic paper was immediately rolled up. Additionally, the surface of the Yankee dryer was lightly coated with trichlorethylene, which is commonly used. The obtained polyester synthetic papers were designated as Examples 1 to 12 and Comparative Examples 1 to 6, respectively.
Using these, create a bag with a contact area of 140 cm ² and add 7 g of UCC medium ground coffee.
It was sealed with a heat sealer. Using these bags, the absorbance of the extract and the amount of powder contained in the extract were measured. The strength and weight of the polyester synthetic paper were also measured. Table 1 lists the results of these tests. Comparative Example 7 The sheath part was made of polyethylene with a melting point of 115°C instead of the copolymerized polyester composite binder fiber.
A bag with a contact area with the liquid of 140 cm 2 was prepared in the same manner as in Example 1, except that a polyolefin composite binder fiber (5D, cut length 5 mm) having a core made of polypropylene with a melting point of ¹⁶⁰ °C was used. , and each performance was measured in the same manner. Table 1 shows the results of these tests. With this bag, the strength was slightly insufficient and the amount of powder generated was large due to insufficient adhesion. 【table】

Claims (1)

[Claims] 1. Consisting of polyester fibers, low melting point polyethylene terephthalate composite binder fibers, and cellulose fibers, the polyester fibers are 20 to 65% by weight, the binder fibers are 10 to 60% by weight, and the degree of freeness is
A synthetic paper for coffee or tea bags having a basis weight of 10 to 40 g/m ² and containing 5 to 50% by weight of 100 to 400 cellulose fibers. [The freeness (unit: ml) here is JIS
This is the value measured using the 2.1 Canadian standard method of the pulp freeness test method specified in P8121. ]