CN113756110A

CN113756110A - Low-heat-conduction pressure-resistant decorative patch and preparation method thereof

Info

Publication number: CN113756110A
Application number: CN202110499833.7A
Authority: CN
Inventors: 潘伟; 习珈维
Original assignee: Junwon Energy Saving Technology Co ltd
Current assignee: Junwon Energy Saving Technology Co ltd
Priority date: 2021-05-08
Filing date: 2021-05-08
Publication date: 2021-12-07
Anticipated expiration: 2041-05-08
Also published as: CN113756110B

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a low-heat-conduction pressure-resistant decorative patch and a preparation method thereof. A low heat conduction resistance to compression decoration paster includes from the top down in proper order: the adhesive comprises an anti-damage layer, a low-heat-conduction decorative layer, a patch layer and a base layer; the base material comprises: at least one of polytetrafluoroethylene, glass fiber, polyester fiber, polyethylene and polypropylene. The low-heat-conduction and pressure-resistant decorative patch prepared by the method disclosed by the invention is green and environment-friendly in preparation raw materials, and migration of inorganic particles is avoided and the weather resistance of the decorative patch is enhanced through the synergistic effect among the organic polymer emulsion, the cellulose ether and other auxiliaries.

Description

Low-heat-conduction pressure-resistant decorative patch and preparation method thereof

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to a low-heat-conduction pressure-resistant decorative patch and a preparation method thereof.

Background

With the remarkable improvement of the productivity level of the country and the gradual expansion of the industrialization scale, the development of the construction industry gradually follows the concepts of low carbon, environmental protection and sustainable development, so that the overall situation of the construction industry can be improved, and the social progress can be promoted. Based on this, the insulation wall body has a large energy consumption as the building industry, and the design of optimizing and improving the insulation wall body becomes the key and difficult point of research of researchers.

At present, the heat insulation wall is arranged through the bonding structure of the film layers, but the material arrangement between the film layers leads to poor bearing capacity between the wall and the external environment or between materials inside the wall, the wall can be separated after being used for a long time, and the difficulty and the cost of building work are increased.

Chinese patent 202010474420.9 discloses a reflective heat-insulation decorative patch and a preparation method thereof, wherein the reflective heat-insulation decorative patch which can reduce the elastic modulus value of hardened mortar, inhibit saltpetering and can be firmly bonded is obtained by preparing a patch bottom layer and a reflective heat-insulation decorative layer in the disclosed patent, but the weight ratio is larger in the disclosed patent, quartz sand with different particle sizes causes poor heat-insulation effect of a heat-insulation wall body in the using process, the quartz sand has higher heat conductivity coefficient, particularly, the void ratio among fillers can be reduced after the quartz sand with different particle sizes is compounded, the contact ratio among preparation raw materials is increased, a communicated heat-conduction network chain is formed, and the heat-insulation effect of the wall body is influenced.

In order to further optimize the feasibility of preparing raw materials, the selection of raw materials and processes which are suitable for use in the field of thermal insulation walls remains an important research direction for researchers.

Disclosure of Invention

In order to solve the above technical problem, a first aspect of the present invention provides a low thermal conductivity and pressure resistant decorative patch, which comprises, from top to bottom: the adhesive comprises an anti-damage layer, a low-heat-conduction decorative layer, a patch layer and a base layer;

the base material comprises: at least one of polytetrafluoroethylene, glass fiber, polyester fiber, polyethylene and polypropylene.

As a preferable technical scheme, the low-heat-conductivity decorative layer is prepared by organic polymer emulsion.

As a preferred technical scheme, the organic polymer emulsion is selected from anionic emulsion and/or cationic emulsion.

As a preferable technical scheme, the anion emulsion contains carboxyl and/or sulfonic hydrophilic groups.

As a preferable technical solution, the raw material for preparing the low thermal conductive decoration layer further comprises at least one of a dispersant, a water retention agent and a thickener.

As a preferred technical scheme, the water retaining agent is selected from at least one of cellulose ether, acrylamide-acrylate copolymer and starch graft polymer.

As a preferred embodiment, the cellulose ether is at least one selected from nonionic cellulose ethers, anionic cellulose ethers, and cationic cellulose ethers.

As a preferred technical scheme, the cellulose ether contains methoxyl; the content of the methoxyl is 19-30%.

The invention provides a preparation method of a low-heat-conduction pressure-resistant decorative patch, which comprises the following steps:

1) coating a patch layer on the surface of the base layer, and then coating a low-heat-conductivity decorative layer on the upper surface of the patch layer;

2) placing the film layer coated in the step 1) in a curing chamber for curing, then coating the anti-damage layer on the upper surface of the low-heat-conductivity decorative layer, and curing to obtain the low-heat-conductivity anti-pressure decorative patch.

As a preferable technical scheme, the temperature of the curing room in the step 2) is controlled to be 20-25 ℃, and the relative humidity is 40-60%.

Has the advantages that: the low-heat-conduction pressure-resistant decorative patch prepared by the invention has the following advantages:

1. the decorative patch with low heat conduction and pressure resistance prepared by the invention has good bonding performance among layers, avoids the separation from a heat insulation plate in the using process, prolongs the service life, and reduces the problem of difficult construction rework of the heat insulation wall body for the building;

2. the low-heat-conduction pressure-resistant decorative patch prepared by the invention has better pressure resistance, can bear external force impact when a building material is used, and enlarges the application range;

3. the low-heat-conduction pressure-resistant decorative patch prepared by the invention has lower heat-conduction performance and can show excellent heat-insulation performance in the use process of a heat-insulation wall body;

4. the low-heat-conduction pressure-resistant decorative patch prepared by the invention has simple preparation process and easily controlled conditions;

5. the low-heat-conduction and pressure-resistant decorative patch prepared by the method is green and environment-friendly in raw material preparation, effectively inhibits the migration of soluble alkali ions and the alkali return phenomenon through the synergistic effect of the organic polymer emulsion, the cellulose ether with a specific structure and other raw materials, and not only enhances the pressure resistance of the decorative patch, but also enhances the weather resistance of the decorative patch.

Drawings

Fig. 1 is a schematic structural view of a low thermal conductivity and pressure resistant decorative patch in embodiment 1 of the present invention;

in the figure:

1. a damage-resistant layer; 2. a low thermal conductivity decorative layer; 3. a chip mounting layer; 4. a base layer;

Detailed Description

The disclosure may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

The term "prepared from …" as used herein is synonymous with "comprising". The terms "comprises," "comprising," "includes," "including," "has," "having," "contains," "containing," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

The conjunction "consisting of …" excludes any unspecified elements, steps or components. If used in a claim, the phrase is intended to claim as closed, meaning that it does not contain materials other than those described, except for the conventional impurities associated therewith. When the phrase "consisting of …" appears in a clause of the subject matter of the claims rather than immediately after the subject matter, it defines only the elements described in the clause; other elements are not excluded from the claims as a whole.

When an amount, concentration, or other value or parameter is expressed as a range, preferred range, or as a range of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. When a range of values is described herein, unless otherwise stated, the range is intended to include the endpoints thereof and all integers and fractions within the range.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. "optional" or "any" means that the subsequently described event or events may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, is intended to modify a quantity, such that the invention is not limited to the specific quantity, but includes portions that are literally received for modification without substantial change in the basic function to which the invention is related. Accordingly, the use of "about" to modify a numerical value means that the invention is not limited to the precise value. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. In the present description and claims, range limitations may be combined and/or interchanged, including all sub-ranges contained therein if not otherwise stated.

In addition, the indefinite articles "a" and "an" preceding an element or component of the invention are not intended to limit the number requirement (i.e., the number of occurrences) of the element or component. Thus, "a" or "an" should be read to include one or at least one, and the singular form of an element or component also includes the plural unless the stated number clearly indicates that the singular form is intended.

In order to solve the above problems, a first aspect of the present invention provides a low thermal conductivity and pressure resistance decorative patch, which is characterized by comprising, in order from top to bottom: the adhesive comprises an anti-damage layer, a low-heat-conduction decorative layer, a patch layer and a base layer;

In some preferred embodiments, the substrate material is glass fiber.

In some preferred embodiments, the glass fiber is an alkali-resistant glass fiber mesh cloth.

The alkali-resistant glass fiber mesh fabric is purchased from chemical building materials limited company in Hebei.

In some preferred embodiments, the low thermal conductivity decorative layer is prepared from an organic polymer emulsion.

In some preferred embodiments, the organic polymer emulsion is selected from an anionic emulsion and/or a cationic emulsion.

In some preferred embodiments, the anionic emulsion contains carboxyl and/or sulfonic hydrophilic groups.

In some preferred embodiments, the anionic emulsion is a carboxyl-containing hydrophilic group emulsion.

In some preferred embodiments, the carboxyl-containing hydrophilic group emulsion is a styrene-acrylic emulsion.

The styrene-acrylic emulsion described in the present application can be made by the manufacturer and purchased.

In some preferred embodiments, the raw materials for preparing the styrene-acrylic emulsion comprise, by weight: 20-25% of styrene, 1-5% of methyl methacrylate, 20-30% of butyl acrylate, 0.5-1.5% of methacrylic acid, 1-3% of emulsifier, 0.01-0.1% of sodium bicarbonate, 0.2-0.8% of initiator and the balance of water to 100%.

In some preferred embodiments, the preparation method of the styrene-acrylic emulsion comprises the following steps:

(1) adding water into a reaction kettle, then adding sodium bicarbonate, an emulsifier, methyl methacrylate and butyl acrylate, and mixing to obtain a mixture A;

(2) 1/3 taking the total weight of the mixture A obtained in the step (1), adding 1/2 of the total weight of the initiator, continuously heating to 70 ℃, and carrying out heat preservation reaction for 10-30 minutes;

(3) adding the rest mixture A and an initiator into the step (2), heating to 70-80 ℃, and reacting for 45-90 minutes under the condition of heat preservation;

(4) cooling to room temperature, discharging, and filtering.

In some preferred embodiments, the raw material for preparing the low thermal conductive decorative layer further comprises at least one of a dispersant, a water retention agent and a thickener.

In some preferred embodiments, the water retaining agent is selected from at least one of cellulose ether, acrylamide-acrylate copolymer, and starch graft polymer.

In some preferred embodiments, the cellulose ether is selected from at least one of nonionic cellulose ethers, anionic cellulose ethers, cationic cellulose ethers.

In some preferred embodiments, the cellulose ether contains methoxyl groups; the content of the methoxyl is 19-30%.

Wherein, the content of the methoxyl group is 19-30 percent, which means that the content of the methoxyl group in the hydroxypropyl cellulose ether is 19-30 percent of the relative molecular mass of the hydroxypropyl cellulose ether.

In some preferred embodiments, the cellulose ether is hydroxypropyl methyl cellulose ether.

In some preferred embodiments, the hydroxypropyl methylcellulose ether has a hydroxypropyl content of 8-16%.

In some preferred embodiments, the hydroxypropyl methylcellulose ether has a hydroxypropyl content of 7 to 12%.

Wherein, the meaning of the hydroxypropyl content of the hydroxypropyl methylcellulose ether is 7-12 percent means that the hydroxypropyl content in the hydroxypropyl methylcellulose ether accounts for 7-12 percent of the relative molecular mass of the hydroxypropyl cellulose ether.

Hydroxypropyl methylcellulose ether, available from hong hai cellulose limited, jin, is commercially available.

In the experimental process, the applicant finds that the adhesion performance between the decorative patches can be further promoted by adding carboxymethyl cellulose ether with 7-12% of hydroxypropyl content and 19-30% of methoxyl content, and the phenomenon that the prepared material is too quickly condensed to cause the cracking of a film layer is avoided, and the applicant speculates that the reason for the phenomenon is that: the hydroxypropyl groups and the methoxyl groups on the cellulose ether can be associated with water molecules and styrene-acrylic emulsion in the system to form hydrogen bonds, so that the water molecules in the system become bound water, the water molecules can enter the molecular chain of the hydroxypropyl methyl cellulose ether under the interaction of Van der Waals force and the like in the system, a porous network structure is formed around the water molecules under the constraint of the styrene-acrylic emulsion and the hydroxypropyl methyl cellulose ether, and the film forming property of the carboxymethyl cellulose ether with the hydroxypropyl content of 7-12 percent and the methoxyl content of 19-30 percent is cooperated to limit the diffusion of the water molecules, slow down the rapid condensation of the film layer, avoid the cracking problem of the film layer in the using process, enhance the compression resistance of the material, and further ensure that the service life of the material can be prolonged when the heat preservation material is applied.

In some preferred embodiments, the raw materials for preparing the low thermal conductive decoration layer further comprise cristobalite and cement.

In some preferred embodiments, the weight ratio of cristobalite to cement is (5-7): 1.

in some preferred embodiments, the cristobalite has a Mohs hardness of 6 to 7.

Cristobalite, available from Warwey silica powder, Inc., Link harbor.

In some preferred embodiments, the cement is a sulphoaluminate cement.

In some preferred embodiments, the raw material for preparing the low thermal conductive decorative layer further comprises a coagulant, wherein the weight percentage of the coagulant is 20-60 wt% of the hydroxypropyl methyl cellulose ether.

In some preferred embodiments, the retarder is selected from at least one of borax, sodium gluconate, citric acid and sodium tripolyphosphate.

In some preferred embodiments, the coagulant includes, but is not limited to, carbonates, chlorides.

The coagulant includes but is not limited to at least one of lithium carbonate, calcium chloride and lithium chloride.

In the experimental process, the applicant finds that the lithium chloride selected as the coagulant can be cooperated with hydroxypropyl methyl cellulose ether to control the coagulation speed of the material, and in addition, the lithium chloride in the system can react with sulphoaluminate cement to inhibit the generation of soluble alkali in the hydration reaction process, so that the alkali return problem of the material in the preparation process is avoided, and the method is beneficial to the decoration and the aesthetic effect of the material.

In some preferred embodiments, the raw materials for preparing the low-thermal-conductivity decorative layer further comprise a silica material, calcium carbonate and bentonite.

In some preferred embodiments, the silica material is silica aerogel powder.

In some preferred embodiments, the silica aerogel powder has a particle size of 20 to 50 nm.

In some preferred embodiments, the silica aerogel powder has a particle size of 25 to 45 nm.

Silica aerogel powder, model QF, was purchased from nano technologies ltd.

In some preferred embodiments, the weight ratio of calcium carbonate to bentonite is (3-5): 1.

in some preferred embodiments, the low thermal conductive decorative layer preparation raw material comprises, by weight: 20-60% of cristobalite, 1-10% of cement, 1-5% of water-retaining agent, 0.2-1% of coagulant, 1-3% of silicon dioxide material, 10-20% of calcium carbonate, 1-5% of bentonite and the balance of organic polymer emulsion to 100%.

In some preferred embodiments, the raw materials for preparing the patch layer include, by weight: 10% of organic polymer emulsion, 20% of sulphoaluminate cement, 35% of cristobalite and 35% of calcium carbonate.

In some preferred embodiments, the raw materials for preparing the damage-resistant layer comprise, by weight: 10% of organic polymer emulsion, 10% of water-based resin and the balance of water to 100%.

In some preferred embodiments, the temperature of the curing chamber in the step 2) is controlled at 20-25 ℃ and the relative humidity is 40-60%.

The present invention will be specifically described below by way of examples. It should be noted that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention, and that the insubstantial modifications and adaptations of the present invention by those skilled in the art based on the above disclosure are still within the scope of the present invention.

In addition, the starting materials used are all commercially available, unless otherwise specified.

Examples

Example 1

A low heat conduction resistance to compression decoration paster includes from the top down in proper order: the decorative layer comprises an anti-damage layer 1, a low-heat-conductivity decorative layer 2, a patch layer 3 and a base layer 4;

the anti-damage layer 1 is prepared from the following raw materials in percentage by weight: 10% of organic polymer emulsion, 10% of water-based resin and the balance of water to 100%.

The particle size of the organic polymer emulsion is 0.1-0.2 mu m, and the type RC-681AG is purchased from Jiangsu sunrise chemical industry Co., Ltd;

the water-based resin, model HC-2082X, is purchased from Jining Bai chemical engineering Co.

The low-heat-conductivity decorative layer 2 is prepared from the following raw materials in percentage by weight: 45% of cristobalite, 7.5% of cement, 1.5% of water-retaining agent, 0.3% of coagulant, 1% of silicon dioxide material, 16% of calcium carbonate, 4% of bentonite and the balance of organic polymer emulsion to 100%.

The cristobalite has Mohs hardness of 6.5 and is purchased from Wawey silicon micropowder Co., Ltd, Hongyong;

the cement is sulphoaluminate cement;

the water-retaining agent is hydroxypropyl methyl cellulose ether, the hydroxypropyl content is 7-12%, and the water-retaining agent is purchased from Honghai cellulose Co., Ltd of Jinzhou city;

the coagulant is lithium chloride;

the silicon dioxide material is silicon dioxide aerogel powder with the particle size of 25-45nm and the model QF, and is purchased from Nanno science and technology company Limited;

the organic polymer emulsion is styrene-acrylic emulsion, and the preparation raw materials comprise, by weight: 24% of styrene, 2.3% of methyl methacrylate, 25% of butyl acrylate, 0.9% of methacrylic acid, 1.2% of emulsifier, 0.005% of sodium bicarbonate, 0.4% of initiator and the balance of water to 100%.

(2) 1/3 taking the total weight of the mixture A obtained in the step (1), adding 1/2 of the total weight of the initiator, continuously heating to 70 ℃, and carrying out heat preservation reaction for 20 minutes;

(3) adding the rest mixture A and an initiator into the step (2), heating to 78 ℃, and carrying out heat preservation reaction for 60 minutes;

(4) cooling to room temperature, discharging, and filtering.

The preparation raw materials of the patch layer 3 comprise the following components in percentage by weight: 10% of organic polymer emulsion, 20% of sulphoaluminate cement, 35% of cristobalite and 35% of calcium carbonate.

The organic polymer emulsion is styrene-acrylic emulsion, and the preparation method refers to the preparation method of the styrene-acrylic emulsion of the low-heat-conduction decorative layer;

the base layer 4 is made of alkali-resistant glass fiber mesh cloth with the thickness of 0.2mm, and is purchased from neutral chemical building materials GmbH in Hebei.

A preparation method of a low-thermal-conductivity and pressure-resistant decorative patch comprises the following steps:

1) adding a patch layer preparation raw material into a dispersion machine, controlling the rotating speed to be 180r/min, stirring for 15 minutes, coating the obtained slurry on the surface of a base layer, and putting the base layer into a curing room with the temperature of 22 ℃ and the relative humidity of 58% for curing for 8 hours;

2) then sequentially adding the raw materials for preparing the low-thermal-conductivity decorative layer, namely cristobalite, cement, a water-retaining agent, a coagulant, a silicon dioxide nano material, calcium carbonate, bentonite and an organic polymer emulsion into a dispersing agent, controlling the rotating speed to be 200r/min, stirring for 10 minutes, and coating the obtained slurry on the surface of the patch cured in the step 1);

3) placing the film layer coated in the step 2) in a curing room, controlling the temperature at 25 ℃ and the relative humidity at 50%, and curing for 8 hours;

4) and stirring and mixing the raw materials for preparing the anti-damage layer in a stirrer, coating the raw materials on the upper surface of the patch cured in the step 3), placing the patch in a curing chamber, controlling the temperature at 23 ℃ and the relative humidity at 50%, and curing for 8 hours to obtain the decorative patch with low heat conductivity and pressure resistance.

Example 2

The specific implementation manner of the decorative patch with low thermal conductivity and pressure resistance is the same as that of the embodiment 1, and is different from the embodiment 1 in that: the weight percentage of the water retention agent in the raw materials for preparing the low-heat-conductivity decorative layer is 0.1 percent.

Example 3

The specific implementation manner of the decorative patch with low thermal conductivity and pressure resistance is the same as that of the embodiment 1, and is different from the embodiment 1 in that: the cristobalite in the raw materials for preparing the low-heat-conduction decorative layer is quartz sand, and the particle size of the quartz sand is 0.18-0.25 mm.

Example 4

The specific implementation manner of the decorative patch with low thermal conductivity and pressure resistance is the same as that of the embodiment 1, and is different from the embodiment 1 in that: the coagulant in the raw material for preparing the low-heat-conduction decorative layer is lithium carbonate.

Example 5

The specific implementation of a low thermal conductivity and pressure resistance decorative patch is the same as that in example 4, and is different from example 4 in that: the raw materials for preparing the low-heat-conduction decorative layer also comprise 0.1% of tartaric acid serving as a retarder.

Example 6

The specific implementation manner of the decorative patch with low thermal conductivity and pressure resistance is the same as that of the embodiment 1, and is different from the embodiment 1 in that: the organic polymer emulsion is purchased, model

Purchased from basf, germany.

And (3) performance testing:

1. and (3) testing the compressive strength: the decorative patches with low thermal conductivity and compression resistance prepared in examples 1 to 6 were used for compression resistance tests, the test standards refer to GB/T15231.2-94, the compression strength tests of the prepared materials 1d, 3d and 28d were tested, and the test results are shown in Table 1 below.

Table 1:

2. the low-thermal-conductivity and compression-resistant decorative paste prepared in the application example 1 is used for a thermal conductivity test, the test method refers to GB/T13475-2008, and the test results are counted in the following table 2.

Table 2:

experiment of	Coefficient of thermal conductivity (W/m. K)
		Example 1	0.098

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The utility model provides a decorate paster of low heat conduction resistance to compression which characterized in that includes from the top down in proper order: the adhesive comprises an anti-damage layer, a low-heat-conduction decorative layer, a patch layer and a base layer;

2. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 1, wherein the decorative layer with low thermal conductivity is prepared from organic polymer emulsion.

3. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 2, wherein the organic polymer emulsion is selected from anionic emulsion and/or cationic emulsion.

4. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 3, wherein the anionic emulsion contains carboxyl and/or sulfonic hydrophilic groups.

5. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 1 or 2, wherein the raw material for preparing the decorative layer with low thermal conductivity further comprises at least one of a dispersant, a water retention agent and a thickener.

6. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 5, wherein the water retention agent is at least one selected from cellulose ether, acrylamide-acrylate copolymer, and starch graft polymer.

7. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 6, wherein the cellulose ether is at least one selected from nonionic cellulose ether, anionic cellulose ether and cationic cellulose ether.

8. The decorative patch with low thermal conductivity and pressure resistance as claimed in claim 7, wherein the cellulose ether contains methoxy groups; the content of the methoxyl is 19-30%.

9. A method for preparing a decorative patch with low thermal conductivity and pressure resistance according to any one of claims 1-9, comprising the following steps:

10. The method for preparing a decorative patch with low thermal conductivity and pressure resistance according to claim 9, wherein the temperature of the curing room in the step 2) is controlled at 20-25 ℃ and the relative humidity is 40-60%.