KR101329058B1 - Polyurethane resin composition for casting for the upper of shoes having excellent workability - Google Patents

Abstract

The present invention relates to a polyurethane resin composition for upper leather of shoes with superior usability and, more particularly, to a two liquid type resin composition containing a main agent part and a curing agent part. The main material part contains 60-70 wt% of polyol, 25-35 wt% of amino alcohol, 3-8 wt% of a crosslinking agent, 1-5 wt% of pigments, and 1-5 wt% of additives. The curing agent part contains 180-250 parts by weight of one or more selected among polyol, polyamine, and a mixture thereof with respect to 100 parts by weight of one or more isocyanate mixtures selected among hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDT), isophorone diisocyanate (IPDI), cyclohexylmethane diisocyanate (H12MDI), methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), and a mixture thereof.

Description

POLYURETHANE RESIN COMPOSITION FOR CASTING FOR THE UPPER OF SHOES HAVING EXCELLENT WORKABILITY

The present invention relates to a polyurethane resin composition for footwear upper with excellent workability, and more particularly includes amino alcohol as a monomer which contributes to the strength, toughness and mechanical properties of the composition together with polyols and isocyanates which are the main raw materials of the polyurethane composition. By doing so, it relates to a polyurethane resin composition for shoe uppers having excellent workability, shoe uppers and shoes comprising the same.

Currently, shoe materials used in Korea can be divided into sole material and upper material. Among them, the material for shoe uppers is mainly used for canvas, rear 89, double weave, piqué, golden velvet, and mesh. In addition, materials such as rubber, TPU, TPE, and polyurethane are used as the material for decorating the pattern on the upper of the shoe upper, and the shoes manufactured using the above materials are manufactured through three processes of cutting, stitching, and assembly. Lose. Among the above processes, Stitching has so many processes and requires skilled workers that the labor wage in Korea has risen and the price competitiveness in the market has decreased significantly. As a result, the production base of the shoe manufacturing industry is low-wage. And gradually moved to China, Indonesia and Vietnam.

Currently, the development of footwear that maximizes functionality and fashion is being developed as a way to maintain its competitiveness in the high-wage domestic shoe manufacturing industry.However, the difficulty of developing functional materials, the complexity of the manufacturing process, and the small quantity production Due to the difficulty, it is being attempted only in some limited fields.

Meanwhile, as another method, a shoe manufacturing process using a mold casting method has been attempted. The mold casting method has the advantage of relatively simple manufacturing process, and the number of manpower required to lower the labor wage, but when using a conventional polyurethane or polyurea composition, workability is considerably poor and mechanical material There is a problem that the quality of the final product is poor because the physical properties are not sufficiently supported.

In order to solve the problems as described above, the present invention provides a polyurethane resin composition for shoe uppers having improved strength, toughness and mechanical properties by polymerizing amino alcohol, which is a monomer, into a main raw material of polyurethane, and a mold casting method. To improve the workability of the shoe manufacturing process using, and also to provide a high quality shoe upper and shoes containing the polyurethane resin composition for shoe uppers.

In order to solve the above object, the present invention as one aspect

In the two-component resin composition comprising a main portion and a hardener portion, the main portion includes 60 to 70 wt% of a polyol, 25 to 35 wt% of an amino alcohol, 3 to 8 wt% of a crosslinking agent, 1 to 5 wt% of a pigment, and 1 to 5 wt% of an additive. %, Wherein the hardener is hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDT), isophorone diisocyanate (IPDI), cyclohexylmethane diisocyanate, H ₁₂ MDI), methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and 100 parts by weight of one or more isocyanate mixtures selected from the group consisting of a polyol having a hydroxyl group , At least one horn selected from the group consisting of polyamines and mixtures thereof Made by mixing 250 parts by weight of water ~ 180, wherein the subject part and the curing agent added 1 provides a polyurethane resin composition for uppers of shoes, characterized in that to be mixed in a volume ratio of 1,

As another aspect, the present invention provides a shoe upper and a shoe comprising the polyurethane resin composition for the shoe upper.

As described above, the resin composition according to the present invention has the characteristics of improving strength, toughness, and mechanical properties of the composition including amino alcohol, which is a monomer, having a relatively low viscosity, and having excellent workability and adhesion to a product. It is possible to provide a polyurethane resin composition for footwear upper with excellent durability,

In addition, the shoe upper and shoes produced using the polyurethane resin composition for footwear upper according to the present invention exhibits excellent effects in hydrolysis resistance, abrasion resistance and bendability.

Hereinafter, the present invention will be described in detail.

As one aspect, this invention is a two-component resin composition which consists of a main part and a hardening | curing agent part, The said main part has 60-70 weight% of polyols, 25-35 weight% of amino alcohols, 3-8 weight% of crosslinking agents, and 1-5 weight of pigments. % And an additive of 1 to 5% by weight, wherein the curing agent part is Hexamethylene Diisocyanate (HDI), Hexamethylene Diisocyanate Trimer (HDT), Isophorone Diisocyanate (IPDI), Cyclohexylmethane 100 parts by weight of one or more isocyanate mixtures selected from the group consisting of cyclohexylmethane diisocyanate (H ₁₂ MDI), methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and mixtures thereof At least one selected from the group consisting of polyols, polyamines and mixtures thereof The mixture is made of 180 to 250 parts by weight of the mixture, characterized in that the main portion and the curing agent to be mixed in a volume ratio of 1: 1, to provide a polyurethane resin composition for footwear uppers.

The polyol in the main part is a raw material that is involved in most of the physical properties of the main part, and imparts functions such as tensile performance, tear performance, and abrasion resistance of the polyurethane product by the mold casting method. The polyol is not particularly limited as long as the polyol has an average of two or more hydroxyl groups, and preferably has a hydroxyl value of 20 to 100 mgKOH / g and a viscosity of 200 to 1200 cps / 25 ° C. Specifically, GP-5000, PP-2000, etc. of KPX Corporation can be mentioned, These can be used individually or in mixture, respectively.

In addition, the content of the polyol is preferably 60 to 70% by weight, when the content of the polyol is less than the lower limit, there is a problem of poor workability due to the increase in viscosity of the composition, if the upper limit exceeds the final curing It is not preferable that the mechanical properties of the finished product are remarkably low, so that the final product of the desired physical properties cannot be made.

The subject portion includes amino alcohols to impart strength, toughness and mechanical properties of the composition as monomers. In general, in the case of manufacturing a polyurethane shoe upper using a mold casting method, it is known that an appropriate viscosity of the polyurethane resin composition at work is 50 to 100 cps / 80 ° C. Unlike conventional polyurethane resin composition, the polyurethane resin composition for shoe uppers containing the amino alcohol exhibits a feature that can satisfy the above viscosity range, and accordingly, a polyurethane shoe upper is manufactured using a mold casting method. In this case, the final cured product can be easily demolded, and since the mold is not contaminated, continuous work is provided.

The amino alcohol may be methanol, ethanolamine, propanolamine, isopropanolamine, butanolamine, isobutanolamine, sec-butanolamine, t-butanolamine, pentanolamine, 2-amino-1-phenylethanol, dimethanolamine, At least one selected from the group consisting of diethanolamine, diisopropanolamine, diisobutanolamine, di-sec-butanolamine, dibutanolamine, dipentanolamine, and N-methylethanolamine, preferably The polyhydric alcohol of the ether system having an amine number of 100 to 300 mgKOH / g may have a hydroxyl value of 800 to 1100 mgKOH / g and a purity of 80 to 100%. Specifically, triisopropanolamine (TIPA) and diethanolamine (DEOA), etc. of DOW Corp. are exemplified, and these may be used alone or in combination.

In addition, the content of the amino alcohol is preferably 25 to 35% by weight. When the content of the amino alcohol is less than the lower limit, there is a problem in that the effect of imparting strength and toughness of the composition is insignificant, and when the amount exceeds the upper limit, the viscosity rises, resulting in poor workability and relatively low content of other compositions. It is not preferable because there is a problem that the resin composition of the desired physical properties can not be prepared.

The cross-linking agent that contributes to controlling the gel time of the polyurethane resin composition for footwear uppers according to the present invention is an aromatic or aliphatic amine compound used as a chain extender and has low reactivity. It is preferable to use functional diamines. The crosslinking agent may be at least one selected from the group consisting of diethyltoluene diamine, polyetheramine, and mixtures thereof, and specific examples thereof include diethyltoluenediamine and the like.

In addition, the content of the crosslinking agent is preferably 3 to 8% by weight. When the content of the crosslinking agent is less than the lower limit, the effect as a chain extender is insignificant, and there is a problem that the curing rate is significantly lowered. When the crosslinking agent is exceeded, the storage stability is lowered and the content of other compositions is relatively low. It is not preferable because there is a problem that can not prepare a composition of the desired physical properties.

The pigment in the main part is to impart the color of the resin composition of the present invention, it is preferable to use 1 to 5% by weight, and is not necessarily limited to the above range depending on the needs of the consumer or the needs of the manufacturer can be appropriately adjusted. have.

In addition, the additives in the main portion is typically used alone or in a mixture of UV-stabilizers, adhesion promoters and the like used in the polyurethane resin composition within the range of 1 to 5% by weight. The UV stabilizer prevents premature degradation due to ultraviolet rays, and it is preferable to add 1 to 3% by weight. When the amount of the UV stabilizer added is less than the lower limit, the effect of preventing premature degradation due to ultraviolet rays is lowered. When the amount of the UV stabilizer is exceeded the upper limit, the effect of preventing premature degradation by ultraviolet rays is no longer improved. On the other hand, there is a risk of lowering other physical properties of the coating composition. Specifically, Ciba's Tinuvin 571 (Tinuvin 571, product name or more) is exemplified.

In addition, the adhesion promoter serves to reinforce the adhesion and strength of the resin composition to other materials, it is preferable to add 1 to 2% by weight. If the amount of the adhesion promoter is less than the lower limit, there is a problem in that adhesion reinforcement to other materials is insufficient, and if the amount exceeds the upper limit, other physical properties of the resin composition may be lowered. Specifically, Dow Corning's silane compound is preferably used.

In addition, in the present invention, the curing agent portion hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDT), isophorone diisocyanate (Isophorone Diisocyanate, IPDI), cyclohexylmethane diisocyanate, H ₁₂ MDI), methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and 100 parts by weight of one or more isocyanate mixtures selected from the group consisting of a polyol having a hydroxyl group It is prepared by mixing 180 to 250 parts by weight of one or more mixtures selected from the group consisting of polyamines and mixtures thereof and maintaining the reaction temperature at 80 to 120 ° C. for 3 to 5 hours.

In addition, the polyol in the curing agent portion is characterized in that at least one mixture selected from the group consisting of polyethylene glycol, polypropylene glycol, polybutylene glycol and polyisoprene glycol, wherein the polyamine in the curing agent portion is polyoxypropylene diamine or polyoxy It is characterized in that at least one mixture selected from the group consisting of propylene triamine, wherein the curing agent portion is preferably NCO content of 10 to 20% by weight, the viscosity may be characterized in that 200 ~ 1500 cps / 25 ℃. .

In addition, the polyurethane resin composition for footwear upper according to the present invention is characterized in that the main portion and the hardener portion is mixed in a volume ratio of 1: 1.

In another aspect, the present invention provides a polyurethane shoe upper comprising the polyurethane resin composition for shoe uppers.

The polyurethane shoe upper, the step of pouring the polyurethane resin composition for shoe upper into a shoe molding mold; Curing the resin composition poured into the shoe molding mold; And demolding the polyurethane shoe upper in the shoe making mold mold.

Looking at the mold casting method in detail, in the step of pouring the shoe upper resin composition to the shoe molding mold, the temperature during pouring of the resin composition is preferably 80 to 85 ℃. When the temperature of the resin composition is less than the lower limit during the pouring, the viscosity of the resin becomes high, so that the precise amount is difficult to be poured, and when the temperature exceeds the upper limit, it is not preferable in terms of storage stability of the resin.

In addition, in the step of curing the resin composition poured into the shoe molding mold, the curing conditions are preferably cured for 15 to 30 minutes at 100 to 150 ℃. If the curing temperature is lower than the lower limit, curing of the composition may be delayed and there is a problem in demolding. If the curing temperature is exceeded, the color of the final cured product may be discolored, which is not preferable. If it is less than, there is a problem that the physical properties of the final cured product are lowered, and even if the upper limit is exceeded, there is no great difference in the degree of curing, which is not preferable.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited thereto.

Example 1

First, to prepare a curing agent, 30% by weight of toluene diisocyanate, 40% by weight of polypropylene glycol GP-5000, and 30% by weight of PP-3000 were mixed and maintained at a reaction temperature of 80 to 90 ° C for 4 hours to obtain an NCO content of 13% by weight. Phosphorus curing agent was prepared.

Next, the main part is manufactured. Here, polyol was used by mixing 20% by weight of polyether polyol PP-2000 and 40% by weight of GP-5000, and amino alcohol was 15% by weight of triisopropanolamine (TIPA) and diethanolamine (DEOA), which are water-soluble alcohols based on monoamines. 20% by weight of the mixture was used. 5% by weight of diethyltoluene diamine as crosslinking agent, 5% by weight of pigment (carbon black + PP2000), 1% by weight of UV stabilizer (Tinuvin 571 from Ciba) and 2% by weight of adhesion promoter (silane compound from Dow Corning) as additives Mixing to prepare a polyurethane resin composition for shoe uppers.

Example 2

First, to prepare a curing agent, 32% by weight of toluene diisocyanate, 38% by weight of polypropylene glycol GP-5000, and 30% by weight of PP-3000 were mixed and maintained at a reaction temperature of 80 to 90 ° C for 4 hours to produce an NCO content of 14% by weight. Phosphorus curing agent was prepared.

Next, the main part is manufactured. Here, polyol was used by mixing 23% by weight of polyether polyol PP-2000 and 40% by weight of GP-5000, and amino alcohol was 16% by weight of triisopropanolamine (TIPA) and diethanolamine (DEOA), which are water-soluble alcohols based on mono amines. 10% by weight of the mixture was used. 6% by weight of diethyltoluene diamine as crosslinking agent, 3% by weight of pigment (carbon black + PP2000), 1% by weight of UV stabilizer (Tinuvin 571 from Ciba) and 1% by weight of adhesion promoter (silane compound from Dow Corning) as additives Mixing to prepare a polyurethane resin composition for shoe uppers.

Example 3

First, to prepare a curing agent, 35% by weight of toluene diisocyanate, 35% by weight of polypropylene glycol GP-5000 and 30% by weight of PP-3000 were mixed and maintained at a reaction temperature of 80 to 90 ° C for 4 hours to obtain an NCO content of 15% by weight. Phosphorus curing agent was prepared.

Next, the main part is manufactured. Herein, polyol was used by mixing 20% by weight of polyether polyol PP-2000 and 45% by weight of GP-5000, and amino alcohol was 15% by weight of triisopropanolamine (TIPA) and diethanolamine (DEOA), which are water-soluble alcohols based on mono amines. 10% by weight of the mixture was used. 7% by weight of diethyltoluene diamine as crosslinking agent, 1% by weight of pigment (carbon black + PP2000), 1% by weight of UV stabilizer (Tinuvin 571 from Ciba) and 1% by weight of adhesion promoter (silane compound from Dow Corning) as additives Mixing to prepare a polyurethane resin composition for shoe uppers.

Comparative Example 1

First, to prepare a curing agent, 40% by weight of toluene diisocyanate, 30% by weight of polypropylene glycol GP-5000, and 30% by weight of PP-3000 were mixed and maintained at a reaction temperature of 80 to 90 ° C for 4 hours to obtain an NCO content of 17% by weight. Phosphorus curing agent was prepared.

Next, the main part is manufactured. Herein, polyol was used by mixing 26% by weight of polyether polyol PP-2000 and 46% by weight of GP-5000, and amino alcohol was 10% by weight of triisopropanolamine (TIPA) and diethanolamine (DEOA), which are water-soluble alcohols based on monoamines. 10% by weight of the mixture was used. 4% by weight of diethyltoluene diamine as a crosslinking agent, 2% by weight of pigment (carbon black + PP2000), 1% by weight of UV stabilizer (Tinuvin 571 from Ciba) and 1% by weight of adhesion promoter (silane compound from Dow Corning) as additives Mixing to prepare a polyurethane resin composition for shoe uppers.

Comparative Example 2

First, to prepare a curing agent, 40% by weight of toluene diisocyanate, 25% by weight of polypropylene glycol GP-5000 and 35% by weight of PP-3000 were mixed and maintained at a reaction temperature of 80-90 ° C. for 4 hours to produce an NCO content of 18% by weight. Phosphorus curing agent was prepared.

Next, the main part is manufactured. Here, polyol was used by mixing 20% by weight of polyether polyol PP-2000 and 35% by weight of GP-5000, and amino alcohol was 15% by weight of triisopropanolamine (TIPA) and diethanolamine (DEOA), which are water-soluble alcohols based on monoamines. 25% by weight of the mixture was used. 6% by weight of diethyltoluene diamine as a crosslinking agent, 2% by weight of pigment (carbon black + PP2000), 1% by weight of UV stabilizer (Tinuvin 571 from Ciba) and 1% by weight of adhesion promoter (silane compound from Dow Corning) as additives Mixing to prepare a polyurethane resin composition for shoe uppers.

Details of the Examples 1 to 3, Comparative Example 1 and Comparative Example 2 are shown in Table 1 below.

Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 subject Polyol 60 63 65 72 50 PP-2000 20 23 20 26 20 GP-5000 40 40 45 46 35 Amino alcohol 27 26 25 20 40 TIPA 15 16 15 10 15 DEOA 20 10 10 10 25 Cross-linking agent
(Chain Extender) Diethyltoluene
Diamine 5 6 7 4 6 Pigment Carbon black
+ PP2000 5 3 One 2 2 additive UV stabilizer One One One One One Adhesion promoter 2 One One One One Sum 100 100 100 100 100 Hardener TDI 30 32 35 40 40 GP5000 40 38 35 30 25 PP3000 30 30 30 30 35 Sum 100 100 100 100 100 Reaction temperature 80 ~ 90 80 ~ 90 80 ~ 90 80 ~ 90 80 ~ 90 Reaction time 4 hours 4 hours 4 hours 4 hours 4 hours NCO% 13 14 15 17 18

Physical property test of resin composition

After the specimens were prepared using the resin compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2, the physical properties were tested according to the following test methods.

At this time, the specimen used in this test was produced under the following conditions.

-Molding Mold: Model Solution Co., Ltd.'s Polyurethane Molding Mold

-Temperature at pouring: 80 ~ 85 ℃

-Conditions for curing and demolding: demolding after curing at 125 ℃ for 20 minutes

1. Hydrolysis Test

The specimens prepared using the resin compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were immersed in NaOH (10%) solution for 24 hours, washed in running water, and dried in a natural state to dry the specimens. The crack state was confirmed.

(?: Good,?: Normal, X: poor)

2. Wear Resistance-Taber Abrasion Test Method

After fixing the specimen prepared by using the resin composition prepared in Examples 1 to 3, Comparative Examples 1 and 2 to the rotating disc, the wear ring freely rotating on the specimen by applying a constant load to the degree of wear It was confirmed.

(Type of wear wheel: CS-17, Weight of wear wheel: 1Kg, Number of revolutions: 1,000 times)

(?: Good,?: Normal, X: poor)

3. Impact resistance

After dropping steel balls at a height of 300 mm on the specimens prepared using the resin compositions prepared in Examples 1 to 3 and Comparative Examples 1 and 2, it was confirmed whether the specimens were peeled or cracked.

(?: Good,?: Normal, X: poor)

4. Bendability

After bending the specimen prepared using the resin compositions prepared in Examples 1 to 3, Comparative Examples 1 and 2, it was confirmed whether the specimen peeled or cracked.

(?: Good,?: Normal, X: poor)

5. UV stability

After cutting the specimen prepared by using the resin composition prepared in Examples 1 to 3, Comparative Examples 1 and 2 to 10in according to the standards of the American Society for Testing and Materials (ASTM), 300w incandescent lamp at 40 ± 1 ℃ conditions Cured for 24 hours to determine the color change of the specimen.

(?: Good,?: Normal, X: poor)

<Physical test results of the resin composition>

The results according to the physical property test of the resin composition are shown in Table 2 below.

Test Items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 I hydrolyse ◎ ◎ ◎ △ ◎ Wear resistance ◎ ◎ ◎ ◎ △ Impact resistance ◎ ◎ ◎ ◎ × Bendability ◎ ◎ ◎ ◎ × UV stability ◎ ◎ ◎ ◎ ◎

(?: Good,?: Normal, X: poor)

As can be seen in Table 2, the resin composition of Examples or Comparative Examples shows a good degree of physical properties, but in particular in the case of the resin composition of Examples 1 to 3 shows excellent results for all the test items.

On the other hand, Comparative Example 1 was found to be somewhat poor in hydrolysis resistance compared to Examples 1 to 3, in the case of Comparative Example 2 was confirmed that the wear resistance is somewhat insufficient and the durability, such as impact resistance, bending resistance is significantly reduced Can be.

Therefore, it can be seen from the above test results that the polyurethane resin composition for footwear upper according to the present invention is excellent in hydrolysis resistance, excellent mechanical strength including abrasion resistance, impact resistance and bendability, and excellent UV stability. have.

The present invention has been described in detail through specific embodiments, but the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art to which the present invention pertains within the scope of the technical idea of the present invention. It is possible. Therefore, it will be apparent that such modifications belong to the technical scope of the present invention.

Claims (7)

In the two-component resin composition comprising the main portion and the curing agent portion,
The main part consists of 60 to 70% by weight of polyol, 25 to 35% by weight of amino alcohol, 3 to 8% by weight of crosslinking agent, 1 to 5% by weight of pigment and 1 to 5% by weight of additive,
The hardener is hexamethylene diisocyanate (HDI), hexamethylene diisocyanate trimer (HDT), isophorone diisocyanate (IPDI), cyclohexylmethane diisocyanate (H ₁₂ MDI), methylene Polyols having a hydroxyl group, polyamines and their compounds based on 100 parts by weight of at least one isocyanate mixture selected from the group consisting of diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and mixtures thereof It is made by mixing 180 to 250 parts by weight of one or more mixtures selected from the group consisting of mixtures,
The main portion and the curing agent portion is characterized in that the mixture in a volume ratio of 1: 1, excellent workability polyurethane resin composition for footwear upper.
The method of claim 1,
The amino alcohols in the subject area are metaolamine, ethanolamine, propanolamine, isopropanolamine, butanolamine, isobutanolamine, sec-butanolamine, t-butanolamine, pentanolamine, 2-amino-1-phenylethanol, di At least one selected from the group consisting of methanol amine, diethanol amine, diisopropanol amine, diisobutanol amine, di-sec-butanol amine, dibutanol amine, dipentanol amine and N-methylethanol amine, Polyurethane resin composition for footwear upper with excellent workability.
The method of claim 1,
The crosslinking agent in the main portion is at least one selected from the group consisting of diethyltoluene diamine and polyether amine, excellent workability polyurethane resin composition for footwear upper.
The method of claim 1,
The polyol in the curing agent portion is at least one mixture selected from the group consisting of polyethylene glycol, polypropylene glycol, polybutylene glycol and polyisoprene glycol,
The polyamine in the curing agent portion is characterized in that at least one mixture selected from the group consisting of polyoxypropylene diamine or polyoxypropylene triamine, excellent workability polyurethane resin composition for footwear.
A polyurethane shoe upper comprising the polyurethane resin composition for shoe upper according to any one of claims 1 to 4.
The method of claim 5,
The polyurethane shoe upper,
Pouring the polyurethane resin composition for footwear upper into a shoe molding mold; Curing the resin composition poured into the shoemaking mold mold; And demolding the polyurethane shoe upper in the shoe making mold mold.
Shoes comprising a polyurethane shoe upper according to claim 5.