Temporary curing agent for wood and cured construction wood

Abstract

To provide a temporary curing agent for wood capable of suppressing moisture absorption of wood.SOLUTION: A temporary curing agent for wood of the present invention includes at least a reactive water-based acrylic silicone polymer, a hardening agent, and a water repellent. The content of the water repellent is 0.25 mass% or more and less than 3.0 mass% relative to the total mass of the temporary curing agent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a technique for curing lumber stored at a construction site. [Background technology]

[0002] Building materials delivered to a construction site are often stored covered in protective protective sheets. For example, wood delivered to the site may be covered in a wrap (a transparent film made of polyvinylidene chloride, etc.), but it is extremely time-consuming to cover the large amount of wood used with the wrap and then peel it off when it is used. Furthermore, the wrap becomes a large amount of waste after use, so it is hard to say that this method is environmentally friendly.

[0003] The dimensions of wood change depending on its moisture content. The equilibrium moisture content of wood varies depending on the external environment, but in Japan the average value outdoors is 15%, and it is slightly lower indoors. The Standard Specifications for Construction Work, JASS11 Woodwork (Architectural Institute of Japan), stipulates that the moisture content of wood when delivered to a construction site should be 20% or less for structural materials, 15% or less for finish materials, and 13% or less for finishing materials. Wood is dried at sawmills to ensure that its moisture content is below these values ​​before it is shipped. In recent years, from the perspective of preventing global warming, attention has been focused on the large-scale construction of wooden buildings that use large amounts of wood, due to the low carbon dioxide emissions and high carbon fixation during manufacturing. As the scale of wooden construction work increases, the period between delivery to the site and construction tends to become longer, and the moisture content of wood stored on site can change due to factors such as humidity and rainfall. When wood expands and contracts, it can deviate from the designed dimensions, making it impossible to join wooden parts such as columns and beams to form a frame, or the position of holes at the joints of components can shift, preventing the insertion of metal fittings and making it impossible to join parts. One method of suppressing dimensional changes involves injecting chemicals such as dimensional stabilizers into wood (e.g., Patent Document 1), but this requires large-scale, dedicated equipment that can control the temperature and pressure while confining wood of the size used in construction, which is costly and time-consuming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-234004 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a temporary curing agent for wood that can be applied to wood brought into a construction site, and in particular to provide a temporary curing agent for wood that has excellent dimensional stability. [Means for solving the problem]

[0006] The means for solving the problems of the present invention are as follows. 1. Contains at least a reactive water-based acrylic silicone polymer, a curing agent, and a water repellent; A temporary curing agent for wood, comprising the water repellent in an amount of 0.25 mass % or more and less than 3.0 mass % based on the total amount. 2. Smectite powder adsorbed with polycarbodiimide is contained in an amount of 0.2% by mass or more and 4% by mass or less based on the total amount, 1. The temporary curing agent for wood according to 1, characterized in that it contains 0.3% by mass or more and 6% by mass or less of scaly silica powder based on the total amount. 3. A temporary curing agent for wood according to 1. or 2., characterized in that it contains an ultraviolet absorber in an amount of 0.3% by mass or more and 6% by mass or less based on the total amount. 4. The temporary curing agent for wood described in 1. or 2. is applied in an amount of 3 g / m2 in solids. 2 More than 60g / m 2 A cured building timber characterized by having, on at least a portion thereof, a coating film as follows: [Effects of the Invention]

[0007] The temporary curing agent for wood (hereinafter also referred to as temporary curing agent) of the present invention can protect construction lumber stored on-site. The temporary curing agent of the present invention can prevent moisture absorption due to humidity changes, rainfall, etc., thereby suppressing fluctuations in the moisture content of construction lumber and reducing the amount of dimensional change due to moisture content fluctuations. In particular, the temporary curing agent of the present invention can significantly suppress an increase in moisture content when the lumber is wet for only a short time, thereby suppressing dimensional increase when the lumber becomes wet due to sudden rainfall, etc. The temporary curing agent of the present invention is low-cost and easy to apply to lumber, so it can suppress dimensional change in lumber at low cost. The temporary curing agent of the present invention is useful as a temporary curing paint to be applied to lumber stored on-site until construction. The temporary curing agent of the present invention can be applied in advance to lumber processed into a predetermined shape at a sawmill or the like, and the construction lumber to which the temporary curing agent of the present invention has been applied can be assembled as a building as is. Therefore, by using the temporary curing agent of the present invention, the amount of work at the construction site can be reduced, and the amount of waste generated can also be reduced. The temporary curing agent of the present invention is effective even when applied thinly, so there is almost no impact on subsequent work. The temporary curing agent of the present invention containing an ultraviolet absorber can prevent discoloration of building timber due to sunburn. [Brief explanation of the drawings]

[0008] [Figure 1] 10 shows images of a surface onto which water was dropped after a water repellency test and a contact angle test in the evaluation test of the examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] The temporary curing agent for construction of the present invention is applied to construction lumber stored at a construction site, such as wooden pillars, beams, and boards, to form a coating film that covers the construction lumber, protecting the lumber and suppressing dimensional changes due to water absorption. Specifically, the temporary curing agent of the present invention is characterized by containing at least a reactive aqueous acrylic silicone polymer, a curing agent, and a water repellent, with the water repellent content being 0.25% by mass or more and less than 3.0% by mass of the total.

[0010] Reactive aqueous acrylic silicone polymer is an aqueous acrylic silicone polymer that can form a crosslinked structure with glycidyl group etc., and for example, can be an acrylic polymer that has an alkoxysilyl group in its side chain.Reactive aqueous acrylic silicone polymer can be commercially available, for example, can be Gemlac W3108F, Gemlac W3153CF manufactured by Kaneka Corporation, Boncoat SA-6360 manufactured by DIC Corporation, Movinyl LDM7532 manufactured by Japan Coating Resin Co., Ltd., etc., and can also be used by mixing two or more of these. The temporary curing agent of the present invention preferably contains 1.0 mass % or more and less than 12.5 mass % of the reactive aqueous acrylic silicone polymer based on the total mass of the temporary curing agent.

[0011] The curing agent can be any agent capable of forming a crosslinked structure with the reactive aqueous acrylic silicone polymer, without any particular limitations. For example, aminosilane, aminosilane / alkylsilane hydrolysate, diaminosilane hydrolysate, aminosilane / alkylsilane hydrolysate, epoxysilane hydrolysate, etc. can be used. These can be commercially available products, such as Dynasylan HYDROSIL 1151, 2627, 2776, 2909, and 2926 manufactured by Evonik.

[0012] The reactive water-based acrylic silicone polymer and the curing agent are preferably mixed so that the molar ratio of the reactive groups is 30:70 to 70:30, more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:45. The temporary curing agent of the present invention is prepared by mixing a base agent containing at least a reactive water-based acrylic silicone polymer and a hardening liquid containing at least a hardener immediately before use.

[0013] As the water repellent agent, fluorine-based, silicone-based, etc., can be used. For example, fluorine-based agents include Modiper F226 and Modiper FS770 manufactured by NOF Corporation, and Megafac F-552 manufactured by DIC Corporation, and silicone-based agents include various silicone oils.

[0014] The temporary curing agent of the present invention contains a water repellent in an amount of 0.25% by mass or more and less than 3.0% by mass based on the total amount of the temporary curing agent. The reactive aqueous acrylic silicone polymer in the temporary curing agent has a hydrophilic silicone structure, but by containing a water repellent in an amount of 0.25% by mass or more and less than 3.0% by mass based on the total amount of the temporary curing agent, water repellency can be imparted to the wood to which it is applied, and moisture absorption by the wood can be prevented. If the water repellent content is less than 0.25% by mass, the moisture absorption prevention effect is insufficient, while if the water repellent content is 3.0% by mass or more, further moisture absorption prevention is unnecessary, and the increased amount of expensive water repellent compared to other agents results in high costs. In addition, the temporary curing agent of the present invention preferably contains 10 to 40 parts by mass of a water repellent agent per 100 parts by mass of reactive water-based acrylic silicone polymer, and more preferably 15 to 30 parts by mass.

[0015] The temporary curing agent of the present invention preferably contains smectite powder having polycarbodiimide adsorbed thereon (hereinafter also referred to as adsorbed smectite powder). The adsorbed smectite powder is preferably contained in an amount of 0.16% by mass or more and less than 2% by mass of the entire temporary curing agent. Smectite is a clay mineral consisting of layered silicates such as montmorillonite, saponite, stevensite, and hectorite, in which metal ions (aluminum ions, sodium ions, calcium ions, etc.) and silicic acid are bonded to form layers of sheets, and it has water-swelling properties. The intercalation phenomenon of amine compounds into smectite is well known, and polycarbodiimides also strongly adsorb to smectite.

[0016] Polycarbodiimide reacts with carboxyl groups of reactive aqueous acrylic silicone polymers to form N-acylurea compounds. Smectite powder adsorbed with polycarbodiimide forms a covalent bond with the reactive aqueous acrylic silicone polymer to form a composite, thereby imparting strength to the coating film. Furthermore, because smectite is water-swellable, a coating film made from a temporary curing agent containing adsorbed smectite powder can adapt to dimensional changes in wood and prevent deterioration of physical properties due to cracks or other defects in the coating film. The carbodiimide equivalent of the polycarbodiimide is preferably 300 to 600 g / mol. The carbodiimide equivalent represents the number of grams of a polymer containing one equivalent of carbodiimide groups.

[0017] Smectite powder with polycarbodiimide adsorbed thereon can be prepared, for example, by adding appropriate amounts of polycarbodiimide and smectite powder to water, stirring and mixing, leaving to stand for several minutes to several tens of minutes, filtering, and drying. The amounts of polycarbodiimide and smectite powder added are preferably in a mass ratio of 1:0.1 to 0.5. If the amount of polycarbodiimide added is less than 0.1 times the amount of smectite powder added, the effect of adsorbing the polycarbodiimide may be insufficient. On the other hand, if the amount is more than 0.5 times, the unadsorbed polycarbodiimide will be wasted, making it uneconomical.

[0018] The temporary curing agent of the present invention preferably contains scaly silica powder in addition to the smectite powder adsorbed with polycarbodiimide. The scaly silica powder is preferably contained in an amount of 0.25% by mass to 3% by mass of the entire temporary curing agent. The scaly silica powder is preferably contained in an amount of 50 parts by mass to 200 parts by mass per 100 parts by mass of the adsorbed smectite powder. Scaly silica has excellent water resistance and self-film-forming properties, but little swelling. Therefore, a coating film containing scaly silica powder but not adsorbed smectite powder is strong and has little stretchability, but its ability to conform to wood deformation is poor. By including both adsorbed smectite powder and scaly silica powder, the coating film can exhibit a good balance of conformability and water resistance. As the scaly silica powder, for example, commercially available Sun Lovely manufactured by AGCSI Tech Co., Ltd. can be used. Furthermore, the scaly silica powder preferably has a median diameter (D50) of 0.5 μm or more and 3.0 μm or less.

[0019] The temporary curing agent of the present invention is water-based. The solvent must be water, and may contain alcohol-based solvents, ketone-based solvents, etc. that are compatible with water. The amount of solvent relative to the entire temporary curing agent is preferably 40% by mass or more and 95% by mass or less from the viewpoint of coating film formability. The proportion of water in the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The temporary curing agent of the present invention can contain additives such as ultraviolet absorbers, film-forming aids, light stabilizers, preservatives, etc. These additives are optional components, but the inclusion of ultraviolet absorbers is preferred from the viewpoint of preventing discoloration of wood due to sunburn.

[0020] As the ultraviolet absorber, at least one of organic ultraviolet absorbers and inorganic ultraviolet absorbers can be used. The ultraviolet absorber is preferably contained in an amount of 0.2 mass % or more and less than 2.7 mass % based on the total amount of the temporary curing agent. Organic and inorganic UV absorbers can be used in combination, and this is preferred because it can broaden the wavelength band of UV light absorbed.As organic UV absorbers, triazine-based UV absorbers such as BASF's Tinuvin 400, benzotriazole-based UV absorbers such as Adeka STAB LA31, Adeka STAB LA32, and Adeka STAB LA36, manufactured by ADEKA CORPORATION, and HOSTAVIN 3315DISP and HOSTAVIN 3326DISP, manufactured by Clariant Chemicals Co., Ltd. can be used.As inorganic UV absorbers, titanium oxide, zinc oxide, cerium oxide, etc. can be used.

[0021] Since the temporary curing agent of the present invention is an emulsion in which a reactive aqueous acrylic silicone polymer is dispersed in water, it has a minimum film-forming temperature (MFT). The MFT is the lowest temperature at which polymer particles fuse together. If the drying temperature is below the MFT, the polymer particles will not fuse together, resulting in poor film formation and the occurrence of cracks in the coating. Adding a film-forming aid to the temporary curing agent of the present invention makes it easier for the polymer particles to fuse together, thereby lowering the MFT. The MFT of acrylic silicone polymers is approximately 5 to 10°C, but by adding a film-forming aid, the MFT can be lowered to below 0°C, making it possible to create a temporary curing agent that can be used outdoors even in winter. Examples of film-forming aids that can be used include Sumack MP-40 and Sumack MP-70 manufactured by Kao Corporation and Dowanol PNP manufactured by Ando Parachemie Co., Ltd. Additionally, butyl celloserve, butyl carbitol, glycol diacetate, and the like can also be used.

[0022] Hindered amine light stabilizers (HALS) are commonly used as light stabilizers, and are additives that suppress photodegradation of polymers, and are particularly effective in preventing surface degradation. Examples of such light stabilizers include BASF's Tinuvin, ADEKA Corporation's Adeka STAB LA72 and Adeka STAB LA82, and Clariant Chemicals' HOSTAVIN 3051-2DISP and HOSTAVIN 3070DISP.

[0023] As the preservative, any water-soluble wood preservative can be used without any particular limitation, and for example, quaternary ammonium compounds, copper-quaternary ammonium compounds, copper-azole compounds, etc. can be used.

[0024] The temporary curing agent of the present invention is used to cover at least a portion of construction lumber stored at a construction site, and can prevent the lumber from absorbing moisture and suppress dimensional changes due to fluctuations in moisture content. When the temporary curing agent of the present invention is used to cover cedar wood, the change in moisture content (humidity) after 24 hours from a humidity change from 20°C and 25% RH to 20°C and 90% RH is preferably less than 8% in order to minimize dimensional change. The change in moisture content (humidity) is based on the assumption that moisture content will change in a high-humidity environment, and it is more preferable that the change in moisture content (humidity) be 7.6% or less. The smaller the moisture content (humidity) change, the better, but a change of about 7% is practically sufficient to suppress dimensional change. If the change is any smaller, the amount of temporary curing agent used will increase, as will the amount of expensive water repellent used, resulting in higher costs. Furthermore, the change in moisture content (humidity) is preferably 90% or less, and more preferably 85% or less, relative to the moisture content (humidity) when the temporary curing agent of the present invention is not applied.

[0025] Furthermore, when the temporary curing agent of the present invention is used to cover cedar wood, the change in moisture content (water absorption) before and after immersion in distilled water at 20°C for 3 minutes is preferably less than 8% in order to minimize dimensional change. The change in moisture content (water absorption) is based on the assumption that wood stored outdoors will be exposed to rainwater, and a change in moisture content (water absorption) of 7.5% or less is more preferable. While a change in moisture content (water absorption) of around 5% is practically sufficient to suppress dimensional change, a change smaller than this increases the amount of temporary curing agent used and the amount of expensive water repellent used, resulting in higher costs. Furthermore, the change in moisture content (water absorption) is preferably 60% or less, and more preferably 50% or less, relative to the moisture content (humidity) when the temporary curing agent of the present invention is not applied.

[0026] The temporary curing agent of the present invention is applied at a rate of 3 g / m2 in solid content to the construction timber. 2 More than 60g / m 2 It is preferable to apply it at a rate of 3 g / m or less. 2 If the amount is less than 60g / m, the moisture absorption prevention effect may be insufficient. 2 If the temperature exceeds this limit, further moisture absorption prevention is not necessary, and the amount of temporary curing agent used increases, resulting in higher costs.

[0027] The temporary curing agent of the present invention is used to cover at least a portion of timber for construction. There are no particular restrictions on the type of timber to which it can be applied, and examples include pillar members, beam members, and board materials. The temporary curing agent of the present invention is preferably applied to at least a portion of a joint such as a joint or connection, and more preferably to the entire joint. By suppressing dimensional changes in the joint, poor bonding during construction can be efficiently prevented. The temporary curing agent of the present invention can also be applied to the entire surface of timber for construction.

[0028] The temporary curing agent of the present invention is preferably applied to pre-cut lumber for construction, which has been dried to a predetermined moisture content or less at a sawmill or the like. This reduces the amount of dimensional change from the pre-cut design dimensions and also reduces the amount of work on-site. The temporary curing agent of the present invention can be applied to timber construction by known methods such as spraying, rolling, brushing, etc. Among these, application by spraying is preferred because it is easy to apply to joints processed into complex shapes such as joints and connections. [Example]

[0029] [Preparation of polycarbodiimide-adsorbed smectite powder] A predetermined amount of smectite powder was dispersed in water, and polycarbodiimide (Carbodilite V-10, Nisshinbo Chemical Co., Ltd.) was added in a mass ratio of 1 / 10 of the smectite powder. The mixture was thoroughly stirred for 5 minutes, filtered, and dried to obtain smectite powder with polycarbodiimide adsorbed.

[0030] [Preparation of temporary curing agent] The base material and the curing liquid were mixed to prepare a temporary curing agent 1 consisting of 25% by mass of reactive water-based acrylic silicone polymer (Zemlac W3108F, Kaneka Corporation), 4% by mass of curing agent (Dynasylan HYDROSIL 1151, Evonik), 3% by mass of water repellent (Modiper F226, NOF Corporation), 2% by mass of smectite powder adsorbed with polycarbodiimide, 3% by mass of scaly silica powder (Sun Lovely, AGCSI Tech Co., Ltd.), 5% by mass of film-forming agent (Dowanol PNP, Ando Parachemie Co., Ltd.), 0.7% by mass of inorganic UV absorber (titanium oxide), 2% by mass of organic UV absorber (Tinuvin 400, BASF), 2% by mass of light stabilizer (Tinuvin, BASF), 2% by mass of preservative, 10% by mass of isopropyl alcohol, 6% by mass of propylene glycol, and the remaining water. The hardening liquid is composed of a hardening agent and propylene glycol, and the remaining ingredients are contained in the base material. This temporary curing agent 1 was diluted with water to prepare temporary curing agents with water repellent contents of 0.1 mass %, 0.3 mass %, 1.0 mass %, and 1.5 mass %, respectively.

[0031] Each temporary curing agent was applied to the entire surface of a cedar board (knot-free, 70 x 150 x 10 mm) with a brush, with the amount of liquid included being 200 mg / m 2 The test samples were obtained by applying the agent evenly so that the surface was uniform. The following evaluation tests were carried out on each test sample and on cedar wood without temporary curing agent. The results are shown in Table 1. Figure 1 also shows some images of the surface on which water was dropped after the water repellency test and the contact angle test.

[0032] Change in moisture content (humidity) This test assumes changes in humidity. The temperature was changed from 20°C and 25% RH to 20°C and 90% RH, and after 24 hours the increase in moisture content before and after the humidity change was measured and evaluated according to the following criteria. ○: Less than 8% △: 8% or more but less than 10% ×: 10% or more · Change in moisture content (water absorption) This test simulates rainfall. The test sample was immersed in distilled water at 20°C for 3 minutes, and the increase in water content before and after immersion was measured and evaluated according to the following criteria. ○: Less than 8% △: 8% or more but less than 10% ×: 10% or more

[0033] Water repellency (1 minute) Approximately 1 g of pure water was dropped onto the center of the application surface of the test sample, whose mass had been measured in advance. The mass of the test sample immediately after the water was dropped (W1) and the mass of the test sample after 1 minute had passed and the mass of the test sample after the water had been wiped off (W2) were measured, and the water repellency was calculated using the following formula (1) and evaluated according to the following criteria. ○: 99% or more △: 96% or more but less than 99% ×: Less than 96% Water repellency (%) = (1 - {(W2 - W) / (W1 - W)}) x 100 (1) W: Mass of test specimen before water dripping W1: Mass of the test piece containing approximately 1 g of water immediately after the water drip W2: Mass of the test piece immediately after wiping off the water 1 minute after the water was dropped Water repellency (3 hours) In the above water repellency (1 minute) test, the part "water was wiped off after 1 minute" was changed to "water was wiped off after 3 hours" and the water repellency was calculated and evaluated according to the following criteria. ○: 70% or more △: 50% or more but less than 70% ×: Less than 50%

[0034] ·Contact angle The contact angle of 2 μl of pure water on the main surface of the test sample was measured using a contact angle meter. The measurement was carried out three times, and the average value was used to evaluate the surface according to the following criteria. ○: 85° or more △: 10° or more and less than 85° ×: Less than 10°

[0035] [Table 1]

[0036] The temporary curing agents of Examples 1 to 3 and Comparative Example 3 were able to suppress the change in moisture content during humidity changes to approximately 85% or less, and the change in moisture content assuming rainfall to approximately 55% or less, compared to when no curing agents were applied (Comparative Example 1).

[0037] [Assumed calculation of dimensional change] When joining a 6000mm long cedar beam to a 450mm square cedar pillar, the target cumulative increase in the beam's elongation and pillar width (at the joint between the components) is 7mm or less. If it is 7mm or less, poor jointing during construction can be prevented. Based on the size of cedar, a common building material, at a moisture content of 15%, the expansion and contraction rates for a 1% change in moisture content were assumed to be 0.259% in the tangential direction, 0.093% in the radial direction, and 0.011% in the fiber direction.

[0038] Humidity changes In the case of cedar wood without application, the moisture content (humidity) increases by 8.8% due to humidity changes, as seen in Comparative Example 1 above. When the moisture content increases by 8.8%, the elongation of the beam and the increase in width of the column are as follows. Note that the increase in width of the column was calculated using the estimated value for the tangential direction (cross grain), which has the largest dimensional change. (Beam extension amount) 6m x 0.011% x 8.8(%) = 5.8mm (Column width increase amount) 45cm x 0.259% x 8.8(%) = 10.3mm Since the beam and column expand as a whole, the amount of expansion at the joint between the beam and column is the amount of expansion per surface. That is, the beam elongates by 2.9 mm (= 5.8 / 2), and the width of the column increases by 5.1 mm (= 10.3 / 2), for a cumulative value of 8.0 mm.

[0039] The calculated beam extension (one side) and column width increase (one side) and their totals are shown in Table 2.

[0040] [Table 2]

[0041] As shown in Table 2, the temporary curing agent of the present invention can reduce dimensional changes in wood, keeping dimensional changes at the joint surface between beams and columns to 7 mm or less. In particular, it can suppress dimensional increases when wood gets wet for only a short time due to sudden rainfall, etc. The temporary curing agent of Comparative Example 3 had an excellent moisture absorption prevention effect. However, its dimensional change was 6.3 mm at high humidity and 4.0 mm when wet from rainfall, etc., and it is considered over-spec because it is rare to imagine a situation where such a dimensional change suppression effect is required. Furthermore, it is expensive because it requires an increased amount of temporary curing agent and water repellent agent, which is more expensive than other agents.

Claims

1. A temporary curing agent for wood to protect construction wood stored on-site until construction begins, The composition contains at least a reactive water-based acrylic silicone polymer, a curing agent, and a water repellent agent, The reactive aqueous acrylic silicone polymer is contained in an amount of 0.1% by mass or more and less than 12.5% ​​by mass based on the total amount, The water repellent agent is contained in an amount of 0.3 mass% or more and 1.5 mass% or less based on the total amount, 0.2% by mass or more and 4% by mass or less of smectite powder having polycarbodiimide adsorbed thereon, The composition contains 0.3% by mass or more and 6% by mass or less of scaly silica powder based on the total mass, The composition contains an ultraviolet absorber in an amount of 0.3% by mass or more and 6% by mass or less based on the total amount, The solvent is contained in an amount of 75.7% by mass or more and 95.1% by mass or less based on the total amount, A temporary curing agent for wood, characterized in that the proportion of water in the solvent is 90 mass % or more.

2. The temporary curing agent for wood according to claim 1 is applied in an amount of 3 g / m2 in terms of solid content. ２ 60g / m or more ２ A cured building timber characterized by having, on at least a portion thereof, a coating film as follows:

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