KR102119900B1 - Polyurethane foam composition and polyurethane foam - Google Patents

Abstract

Disclosed are polyurethane foam compositions and polyurethane foams having excellent water absorption.
The polyurethane foam composition and the polyurethane foam according to the present invention are characterized by including a branched type polyurethane resin, a blowing agent, an isocyanate curing agent, a surfactant, and a polyol.

Description

Polyurethane foam composition and polyurethane foam {POLYURETHANE FOAM COMPOSITION AND POLYURETHANE FOAM}

The present invention relates to a polyurethane foam composition and polyurethane foam excellent in water absorption.

In the case of a general polyurethane foam having absorbency, an open cell is formed inside the foam by adding a foaming agent to the foam composition. At this time, since it is difficult to manufacture the polyurethane foam to a desired thickness, an additional slicing process is required after the foam is manufactured.

In particular, the polyurethane foam applied to the medical tape requires excellent water absorption and low density. When a general polyurethane foam is applied to the medical tape, it is difficult to form a thin film thickness foam, and there is a limit to improve the absorption of exudate. .

Accordingly, there is a need for a polyurethane foam having low density and excellent water absorption.

Background art related to the present invention includes Republic of Korea Patent Publication No. 10-2013-0098717 (published on September 5, 2013), the document discloses a polyurethane foam tape and a method for manufacturing the same.

An object of the present invention is to provide a polyurethane foam composition capable of producing a thin film thickness foam.

Another object of the present invention is to provide a polyurethane foam having low density and excellent water absorption.

The polyurethane foam composition according to the present invention for achieving the above object is characterized by comprising a branched type polyurethane resin, a blowing agent, an isocyanate curing agent, a surfactant, and a polyol. do.

The branch chain-type polyurethane-based resin may have a weight average molecular weight of 20000-100000.

The foaming agent may have an average diameter of 0.01 to 100㎛.

With respect to 100 parts by weight of the branch chain-type polyurethane-based resin, it may include 0.1 to 10 parts by weight of a blowing agent.

With respect to 100 parts by weight of the branch chain-type polyurethane-based resin, it may include 1 to 40 parts by weight of an isocyanate curing agent.

The surfactant may be included in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the branch chain-type polyurethane resin.

With respect to 100 parts by weight of the branch chain-type polyurethane-based resin, it may include 20 to 60 parts by weight of polyol.

The polyurethane foam according to the present invention for achieving the above other objects is heat-cured from a composition comprising a branched type polyurethane-based resin, a blowing agent, an isocyanate-based curing agent, a surfactant and a polyol, and It is formed by foaming, and has an absorption of 2.2 to 2.8, and a density of 0.1 to 0.3 g/cm ³ .

The thickness of the polyurethane foam may be 10 ~ 200㎛.

The polyurethane foam composition according to the present invention is applied by a coating method so that heat curing and foaming can be simultaneously performed. Due to this, it is possible to form a polyurethane foam having a thin film thickness. In addition, by containing the polyol in the composition, it is possible to improve the absorbency of the polyurethane foam.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and the ordinary knowledge in the technical field to which the present invention pertains. It is provided to fully inform the holder of the scope of the invention, and the invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Hereinafter, a polyurethane foam composition and a polyurethane foam according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Polyurethane-based resins are widely used as raw materials for foams, elastomers, paints and adhesives. Foam refers to a honeycomb material produced by a polymer reaction that generates bubbles.

The polyurethane foam having absorbency has an open cell structure inside the foam. Such a structure can be formed by adding a blowing agent to the composition and then foaming. At this time, it is difficult to manufacture the thickness of the foam to a thin film thickness, so an additional slicing process is performed.

The foam composition of the present invention includes a foamable branch chain-type polyurethane-based resin, a foaming agent, a curing agent, a surfactant, and a polyol, and it is possible to provide a polyurethane foam capable of thermal curing and foaming at the same time by adjusting their respective contents.

In addition, since the polyurethane foam may have a thin film thickness, an additional slicing process can be omitted.

In addition, the polyurethane foam prepared in the present invention can be applied to medical tapes due to its excellent absorbency and low density.

The polyurethane foam composition of the present invention comprises a branched type polyurethane resin, a blowing agent, an isocyanate curing agent, a surfactant, and a polyol.

Branched type polyurethane resin

Polyurethane is a foamed polymer and has a urethane structure (-NH-CO-O-) in the polymer main chain.

The polyurethane-based resin is produced by polymerizing two monomers, diol and diisocyanate, for example, and a polyurethane-based resin can be produced through a general manufacturing method.

It is preferable that the polyurethane foam composition of the present invention does not include a linear type polyurethane resin having little foamability, and a branched chain type polyurethane resin excellent in foamability.

The linear polyurethane-based resin refers to a polyurethane-based resin having a linear structure without a chain in the polymer main chain.

Branch chain-type polyurethane-based resins have many chains connected to a polymer main chain, and are also called nonlinear polyurethane-based resins. More specifically, it is a form having a urethane structure prepared by reacting polypropylene glycol (PPG) and isophorone diisocyanate (IPDI), and is a form in which the urethane structure extends in branched chains. The branch chain-type polyurethane resin having such a shape may have a weight average molecular weight of 20000 to 100,000. Branched chain-type polyurethane-based resins have random OH groups at the ends of the main chain and branch chains, and OH groups react with NCO during the resin polymerization process. At this time, by the randomly present OH group, as the bubbles are formed between the functional groups in the course of thermal curing and foaming, the branch chain-type polyurethane-based resin can be cured into a complex structure. On the other hand, since the linear polyurethane-based resin has an OH group only at the ends of the main chain, foaming may not be properly performed compared to the branch chain-type polyurethane-based resin. Therefore, it is preferable to include a branched chain-type polyurethane resin capable of foaming in the composition.

In addition, the branch chain type has a relatively small density compared to a linear shape, and is excellent in moldability, thereby forming a soft and low density polyurethane foam.

Polyurethane foam is generally divided into rigid, soft, and semi-rigid. Rigid polyurethane foam is difficult to restore to its original form when deformed by external force, and is mainly used as an insulating material, filler, and the like. The soft polyurethane foam has a soft outer shape and can be easily restored to its original form even if it is deformed by external force, and is mainly used as a cushioning material, absorbent material, sound absorbing material, and the like. The semi-rigid polyurethane foam has an intermediate hardness between hard and soft, and is mainly used for automobile interior materials.

blowing agent

The polyurethane foam composition may be prepared in a foam form having an open cell by foaming it by including a foaming agent. The open cell of the foam may be formed by a gas generated from a foaming agent in the process of foaming the foam composition, and the foam continues to grow and then burst. In addition, as the bubble grows, the bubble wall between the neighboring bubbles and those separating them becomes thinner and may be formed by bursts of bubbles.

The blowing agent is a material that is foamed at a temperature of approximately 100 to 180°C, and preferably contains a microsphere blowing agent having an average diameter of 0.01 to 100 µm. The microsphere blowing agent is uniformly dispersed in the foam composition and provides cushioning properties to the foam, while providing a lightweight effect. The foaming agent may contain 0.1 to 10 parts by weight based on 100 parts by weight of the branch-chain polyurethane-based resin. If less than 0.1 part by weight, the role of the blowing agent may be insufficient, and if it exceeds 10 parts by weight, the blowing agent may rupture too easily, and the surface of the foam may be rough.

Isocyanate curing agent

The polyurethane foam composition contains an isocyanate-based curing agent, thereby increasing the gel content to impart excellent durability.

The isocyanate-based curing agent may contain 1 to 40 parts by weight based on 100 parts by weight of the branch chain-type polyurethane-based resin. When the content is less than 1 part by weight, curing may not be sufficiently performed, and durability may be deteriorated. Conversely, when the content exceeds 40 parts by weight, the polyurethane foam may harden like a solid by over-curing, which may make it unsuitable for medical or skin adhesion.

Examples of the isocyanate curing agent include methyl isocyanate curing agent, naphthyl isocyanate curing agent, organosilicon isocyanate curing agent, tetramethylline diisocyanate curing agent, and phenyl isocyanate curing agent.

Surfactants

The surfactant is uniformly distributed in the polyurethane foam composition to control the size of bubbles, and is also referred to as a foam stabilizer.

The surfactant may be a silicone-based surfactant or the like, and imparts bubble stability and foam uniformity during foam production. In addition, a silicone surfactant and an amine silicone compound may be used in combination, but the present invention is not limited thereto.

The surfactant may contain 0.1 to 10 parts by weight based on 100 parts by weight of the branch-chain polyurethane-based resin.

If the content is less than 0.1 parts by weight, the amount of addition may be small, so it may be difficult to control the bubble size. Conversely, when the content exceeds 10 parts by weight, the dispersibility and compatibility of the surfactant may be lowered and the physical properties may be reduced.

Polyol

Polyol is a polyhydric alcohol, that is, an aliphatic compound having two or more hydroxyl groups (-OH), and has excellent compatibility with a polyurethane-based resin and has high hydrophilicity, thereby improving the absorbency of the polyurethane foam. have.

The polyol may include 20 to 60 parts by weight with respect to 100 parts by weight of the branch chain-type polyurethane-based resin, in order to exhibit excellent water absorption of the foam. When the content is less than 20 parts by weight, it is difficult to expect improvement in absorbency. Since the polyol participates in a curing reaction together with a curing agent, when the polyol exceeds 60 parts by weight, thermal curing may not be properly performed. To this end, when a large amount of a curing agent is added, physical properties may be difficult to control.

The polyurethane foam composition may further include additives including a tackifier, an antistatic agent, etc., in addition to a branched type polyurethane resin, a foaming agent, an isocyanate-based curing agent, a surfactant, and a polyol. However, it is not limited thereto.

In addition, the polyurethane foam composition may be applied to the adhesive layer by a coating method, and then form a polyurethane foam through thermal curing and foaming. Heat curing and foaming can be performed simultaneously at approximately 100 to 180°C, through which a low density foam satisfying 0.1 to 0.3 g/cm ³ can be produced.

The polyurethane foam according to the present invention is formed by thermal curing and foaming from a composition comprising a branched type polyurethane-based resin, a blowing agent, an isocyanate-based curing agent, a surfactant, and a polyol.

In addition, the polyurethane foam has an absorbent amount of 2.2 to 2.8, and a density of 0.1 to 0.3 g/cm ³ , so that it is applied to medical tapes and has an effect of high exudate absorption. When the density of the polyurethane foam is less than 0.1 g/cm ³ , the soft properties of the foam increase, but there is a problem that the foam is easily torn even with a small force. When the density of the polyurethane foam exceeds 0.3 g/cm ³ , the soft properties of the foam may be reduced.

In addition, the thickness of the polyurethane foam may be 10 ~ 200㎛. Polyurethane foam having a thin film thickness has low density and excellent water absorption, and thus can be applied to medical tapes.

The specific examples of the polyurethane foam composition and the polyurethane foam are as follows.

1. Preparation of polyurethane foam

Example 1 and Comparative example 1-3

Branch chain-type polyurethane resin (LHG_PU1) having a weight average molecular weight of 20000, blowing agent (MS-4600FS), curing agent (TKA-100), silicone surfactant (L-580), and polyol (FA-103) having an average diameter of 10 µm. To prepare a polyurethane foam composition comprising a content shown in [Table 1].

After applying the polyurethane foam composition on the adhesive layer, a polyurethane foam having a thickness of 100 μm was prepared through thermal curing and foaming at a temperature of 165° C.

Comparative Example 4

A polyurethane foam was prepared in the same manner as in Example 1, except that the polyurethane foam composition contained a linear polyurethane resin (LHG_PU2).

[Table 1]

The content of the foaming agent, curing agent, surfactant, and polyol included in the polyurethane foam composition was described in parts by weight based on 100 parts by weight of the branch chain type polyurethane resin.

Measurement of absorption: It was measured by the EN13726-1 test method. After cutting the sample of the foam prepared by Example 1 and Comparative Examples 1 to 4 in a horizontal, vertical 2×2 cm ² size, the weight (A _dry ) of the sample in a dried state is measured. After soaking the sample in distilled water at 37° C., the wet sample weight (A _wet ) is measured after 30 minutes.

Absorption amount: (A _wet -A _dry )/A _dry

Referring to Table 1, in the case of Example 1, which satisfies all the contents of the polyurethane foam composition, an absorption amount of 2.5 and a density of 0.2 g/cm ³ are shown.

On the other hand, in Comparative Examples 1 and 2 in which the content of the polyol in the foam composition was 5 parts by weight or less, the absorption amount showed a result of 0.7 or less. In the case of Comparative Example 3 without a surfactant, the results of the absorption amount and density did not satisfy the ranges presented in the present invention. Comparative Example 4 containing a linear polyurethane resin showed a relatively low water absorption compared to Example 1, and the density was also higher than 0.4 g/cm ³ .

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and may be manufactured in various different forms, and having ordinary knowledge in the technical field to which the present invention pertains. It will be understood that a person can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (9)

Branched-type (branched type) polyurethane-based resin, foaming agent, isocyanate (isocyanate)-based curing agent, a surfactant and a polyol (polyol), and based on 100 parts by weight of the branched-chain polyurethane-based resin, 20 to 60 weight of the polyol Polyurethane foam composition comprising a portion.
According to claim 1,
The branch chain-type polyurethane-based resin is a polyurethane foam composition, characterized in that the weight average molecular weight is 20,000 to 100,000.
According to claim 1,
The foaming agent is a polyurethane foam composition, characterized in that the average diameter is 0.01 ~ 100㎛.
According to claim 1,
A polyurethane foam composition comprising 0.1 to 10 parts by weight of a foaming agent relative to 100 parts by weight of the branch chain-type polyurethane resin.
According to claim 1,
Polyurethane foam composition comprising 1 to 40 parts by weight of an isocyanate-based curing agent, based on 100 parts by weight of the branch chain-type polyurethane-based resin.
According to claim 1,
Polyurethane foam composition comprising 0.1 to 10 parts by weight of surfactant, based on 100 parts by weight of the branch chain-type polyurethane-based resin.
delete Branched-type (branched type) polyurethane-based resin, foaming agent, isocyanate (isocyanate)-based curing agent, a surfactant and a polyol (polyol), and based on 100 parts by weight of the branched-chain polyurethane-based resin, 20 to 60 weight of the polyol It is formed by thermal curing and foaming from a composition containing parts,
Polyurethane foam characterized in that the absorption amount is 2.2 to 2.8, and the density is 0.1 to 0.3 g/cm ³ .
The method of claim 8,
Polyurethane foam, characterized in that the thickness of the polyurethane foam is 10 ~ 200㎛.