JP-7856580-B2 - resin particle composition

Inventors

• 田邉 友花

Assignees

• 住友精化株式会社

Dates

Publication Date

20260511

Application Date

20211130

Priority Date

20201209

Claims (5)

1. It comprises water-absorbing resin particles and a fixing member layer provided on at least a portion of the surface of the water-absorbing resin particles, After the caking test performed in the order of (1) to (5) below, at least a portion of the particles remain on the sieve with a mesh size of 850 μm used, and the caking index, as measured by the caking test and shown by the following formula, is 20% or more. The fixing member comprises at least one selected from the group consisting of ethylene-sodium acrylate copolymer, polyamide polymer , and polyester polymer, in a resin particle composition. (1) Place a circular release paper with a diameter of 50 mm on the bottom of a circular stainless steel petri dish with an inner diameter of 52 mm, and sprinkle 2.0 g of a resin particle composition with a particle size of less than 850 μm on top of the release paper. (2) A sample for measurement is obtained by stacking a circular release paper with a diameter of 50 mm, a circular stainless steel petri dish with an outer diameter of 50 mm and a mass of 20 g, and a cylindrical weight of 780 g with a diameter of 45 mm on top of the scattered resin particle composition in this order. (3) Dry the sample in a hot air dryer at 80°C for 1 hour, then allow it to cool to room temperature. (4) After cooling, the resin particle composition is removed from the release paper and recovered, and the entire amount of the recovered resin particle composition is placed on a sieve with a mesh size of 850 μm. (5) After shaking the sieve in a rotary sieve shaker for 5 seconds, check whether any resin particle composition remains on the sieve. Caking index (%) = [Mass of resin particle composition remaining on an 850 μm sieve / (Total mass of resin particle composition remaining on an 850 μm sieve and resin particle composition that passed through an 850 μm sieve)] × 100
2. The resin particle composition according to claim 1, wherein the median particle size is 20 to 600 μm.
3. The resin particle composition according to claim 1 or 2, wherein the fixing member comprises an ethylene-sodium acrylate copolymer.
4. The resin particle composition according to any one of claims 1 to 3, wherein the amount of the fixing member is 0.01 to 10 parts by mass per 100 parts by mass of the water-absorbing resin particles.
5. A resin particle composition according to any one of claims 1 to 4, wherein the saline solution water retention capacity is 30 g/g or more.

Description

This invention relates to a resin particle composition. Among resin particles, superabsorbent resin particles, which have the property of absorbing and retaining water, an essential element in daily life, are widely used in fields such as sanitary materials such as disposable diapers and sanitary products, agricultural and horticultural materials such as water-retaining agents and soil conditioners, and industrial materials such as water-stopping agents and condensation-preventing agents. Since superabsorbent resin particles are usually powders with no adhesive properties, in the above applications they are used as absorbents formed in a sandwich-like structure by scattering superabsorbent resin particles on a fibrous substrate such as nonwoven fabric. In this case, in order to fix the superabsorbent resin particles to the substrate, a method is used in which superabsorbent resin particles are scattered on a fibrous substrate coated with an adhesive (for example, Patent Document 1). International Application No. 2011/043256 Several embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments. In this specification, "acrylic" and "methacrylic" are collectively referred to as "(meth)acrylic." Similarly, "acrylate" and "methacrylate" are referred to as "(meth)acrylate." "(poly)" means both with and without the prefix "poly." In the numerical ranges described stepwise in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. In the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values shown in the examples. The materials exemplified in this specification may be used individually or in combination of two or more. The content of each component in the composition means the total amount of multiple substances present in the composition if there are multiple substances corresponding to each component, unless otherwise specified. "Water-soluble" means solubility of 5% by mass or more in water at 25°C. "Room temperature" means 25±2°C. The term "layer" encompasses not only structural shapes that are formed across the entire surface when observed as a plan view, but also structural shapes that are formed in only a portion of the surface. The resin particle composition according to this embodiment comprises water-absorbing resin particles and a fixing member layer. The resin particle composition has caking properties as measured in a caking test performed in the order of (1) to (5) below. Having caking properties means that at least a portion of the particles remain on the sieve with a mesh size of 850 μm after step (5) of the caking test below. (1) Place a circular release paper with a diameter of 50 mm on the bottom of a circular stainless steel petri dish with an inner diameter of 52 mm, and sprinkle 2.0 g of a resin particle composition with a particle size of less than 850 μm on top of the release paper. (2) A measurement sample is obtained by stacking a circular release paper with a diameter of 50 mm, a circular stainless steel petri dish with an outer diameter of 50 mm and a mass of 20 g, and a cylindrical weight of 780 g with a diameter of 45 mm on top of the scattered resin particle composition in this order. This applies a pressure of 4000 Pa to the resin particle composition. (3) Dry the sample in a hot air dryer at 80°C for 1 hour, then allow it to cool to room temperature. (4) After cooling, the resin particle composition is removed from the release paper and recovered, and the entire amount of the recovered resin particle composition is placed on a sieve with a mesh size of 850 μm. (5) After shaking the sieve for 5 seconds using a rotary sieve shaker, check whether any resin particle composition remains on the sieve. The resin particle composition according to this embodiment has the caking properties measured in the above caking test. For example, when preparing an absorbent, the resin particle composition can be fixed to the fibrous substrate by stacking the resin particle composition and the fibrous substrate and applying pressure and heating, without the need for a separate adhesive. While the above caking test is directly an indicator of the bonding properties between resin particle compositions, a resin particle composition having such caking properties can also be bonded to a fibrous substrate by applying pressure and heating. The resin particle composition according to this embodiment preferably has a caking index of 20% or more, as shown by the following formula. The caking index can be calculated by measuring the mass of the resin particle composition remaining on a sieve with an opening of 850 μm and the mass of the resin particle composition that passed through the sieve with an opening of 850 μm after step (5) of