Cashew phenolic aldehyde amine epoxy resin curing agent containing tetrazole structure as well as preparation method and application of cashew phenolic aldehyde amine epoxy resin curing agent

Abstract

The invention relates to the technical field of epoxy coatings, in particular to a cashew phenolic aldehyde amine epoxy resin curing agent containing a tetrazole structure as well as a preparation method and application of the cashew phenolic aldehyde amine epoxy resin curing agent. The cashew phenolic aldehyde amine epoxy resin curing agent containing the tetrazole structure provided by the invention simultaneously contains primary amine, secondary amine and tertiary amine, so that sufficient reactive hydrogen required by curing is provided, ring-opening reaction can be further promoted, and the curing speed is greatly increased; meanwhile, the hardness of a cured product can be improved by a tetrazole ring structure, and the problem of low hardness caused by 15 carbon long-chain structures in cardanol is solved. Therefore, after the cashew phenolic aldehyde amine epoxy resin curing agent containing the tetrazole structure is matched with epoxy resin, the drying speed is high, the actual drying time is shorter than 4 h, meanwhile, the impact resistance is high, the positive impact and the negative impact can reach 100 cm, the cross-cut adhesive force is level 0, the flexibility is 1 mm, and the hardness is level H or above.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy coatings, and in particular to a tetrazole-containing cardanol aldehyde amine epoxy resin curing agent, and a preparation method and application thereof. Background Art

[0002] Cardanol is a green and environmentally friendly industrial raw material extracted from natural cashew nut shell oil. The presence of its benzene ring structure gives it excellent high temperature resistance, and the C15 long straight chain containing an unsaturated double bond at the meta-position of the benzene ring can enhance the toughness of the system and provide excellent hydrophobicity and self-drying properties. It has become a research hotspot in recent years due to its abundant source, low price, excellent performance and renewability.

[0003] Curing agent is one of the indispensable components in the use of epoxy resin, and plays a very important role in the performance of epoxy resin cured product. Small molecule fat curing agents such as ethylenediamine, diethylenetriamine and triethylenetetramine have the disadvantages of high toxicity, fast curing reaction, intense curing reaction with epoxy resin, short service life, etc., and curing is limited by temperature and humidity conditions. Therefore, the synthesis of cashew phenol aldehyde amine type curing agent with macromolecular chain structure and non-volatile has become a market trend. After the cashew phenol aldehyde curing agent synthesized by Mannich reaction is matched with epoxy resin, it has the advantages of long application period, low curing shrinkage, low toxicity and excellent mechanical properties. However, due to the small variety of raw material fatty amines in cashew phenol aldehyde amine and simple structure, it is gradually unable to meet the market demand for the comprehensive performance of cashew phenol curing agent (such as excellent mechanical properties, adhesion and anti-corrosion performance, etc.), so it is imperative to develop a cashew phenol aldehyde amine epoxy curing agent with a new structure. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a tetrazole-containing cardanol aldehyde amine epoxy resin curing agent and a preparation method and application thereof, wherein the cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure has excellent comprehensive properties (excellent adhesion, impact resistance, hardness and corrosion resistance).

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a tetrazole-containing cardanol aldehyde amine epoxy resin curing agent having a structure shown in Formula 1 or Formula 2:

[0007]

[0008] The present invention also provides a method for preparing the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent described in the above technical solution, comprising the following steps:

[0009] In an inert atmosphere, cardanol and tetrazole-5-acetylhydrazine are mixed, a substance providing formaldehyde monomer is added, and a Mannich reaction and a dehydration reaction are sequentially performed, and then an accelerator is added to obtain the cardanol aldehyde amine epoxy resin curing agent with a tetrazole structure.

[0010] Preferably, the molar ratio of the cardanol, tetrazolium-5-acetylhydrazine and the formaldehyde monomer in the substance providing the formaldehyde monomer is (1.0-1.2): (1.1-1.3): (1.4-1.6).

[0011] Preferably, the substance providing formaldehyde monomer includes paraformaldehyde or a formaldehyde aqueous solution with a mass concentration of 37%.

[0012] Preferably, the mixing temperature is 90-100°C;

[0013] The temperature of adding the substance providing formaldehyde monomer is 75 to 90°C.

[0014] Preferably, the process of the Mannich reaction is: first react at a temperature of 100 to 105° C. for 1 to 2 hours, and then react at a temperature of 145 to 150° C. for 2.5 to 3.5 hours.

[0015] Preferably, the temperature of the dehydration reaction is 100-105° C., the vacuum degree is 2-3 kPa, and the time is 40-50 min.

[0016] Preferably, the accelerator includes one or two of 2,4,6-tris(dimethylaminomethyl)phenol, triethanolamine and N,N-dimethyl-1,3-propylenediamine.

[0017] Preferably, the mass of the accelerator is 2-4% of the total mass of the cardanol, tetrazole-5-acetylhydrazine and the substance providing the formaldehyde monomer.

[0018] The present invention also provides the use of the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent described in the above technical scheme or the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent prepared by the preparation method described in the above technical scheme in the field of coating.

[0019] The present invention provides a tetrazole-containing cardanol aldehyde amine epoxy resin curing agent having a structure shown in Formula 1 or Formula 2:

[0020]

[0021] The present invention contains primary amine, secondary amine and tertiary amine in the tetrazole structure-containing cardanol aldehyde amine epoxy resin curing agent, which not only provides sufficient active hydrogen required for curing, but also further promotes the ring-opening reaction, greatly improving the curing speed; at the same time, the tetrazole ring structure can improve the hardness of the cured product, making up for the problem of low hardness caused by the 15 carbon long chain structure in cardanol. Therefore, the cardanol aldehyde amine epoxy resin curing agent containing tetrazole structure of the present invention has a fast drying speed after being matched with epoxy resin, and the actual drying time is less than 4h, and the impact resistance is strong, both positive and negative impact can reach 100cm, the cross-cut adhesion is level 0, the flexibility is 1mm, and the hardness is above level H. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the infrared spectrum of the tetrazole-containing cashew phenol aldehyde amine epoxy resin curing agent described in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a tetrazole-containing cardanol aldehyde amine epoxy resin curing agent having a structure shown in Formula 1 or Formula 2:

[0024]

[0025] The present invention also provides a method for preparing the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent described in the above technical solution, comprising the following steps:

[0026] In an inert atmosphere, cardanol and tetrazole-5-acetylhydrazine are mixed, a substance providing formaldehyde monomer is added, and a Mannich reaction and a dehydration reaction are sequentially performed, and then an accelerator is added to obtain the cardanol aldehyde amine epoxy resin curing agent with a tetrazole structure.

[0027] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0028] In the present invention, the inert atmosphere is preferably a nitrogen atmosphere.

[0029] In the present invention, the purity of the cardanol is preferably ≥90%.

[0030] In the present invention, the molar ratio of the cardanol to tetrazolium-5-acetylhydrazine is preferably (1.0-1.2): (1.1-1.3), more preferably (1.05-1.15): (1.15-1.25). In an embodiment of the present invention, the molar ratio of the cardanol to tetrazolium-5-acetylhydrazine can be 1:1.1, 1:1.2, 1.2:1.3, 1.15:1.25 or 1.05:1.15.

[0031] In the present invention, the mixing temperature is preferably 90-100° C., more preferably 92-98° C. In an embodiment of the present invention, the mixing temperature may be 90° C., 100° C., 95° C. or 97° C. The present invention does not have any particular limitation on the mixing time, and a time well known to those skilled in the art may be used to ensure complete dissolution.

[0032] In the present invention, the substance providing formaldehyde monomer preferably includes paraformaldehyde or a formaldehyde aqueous solution with a mass concentration of 37%. In the present invention, the molar ratio of the formaldehyde monomer in the cardanol and the substance providing formaldehyde monomer is preferably (1.0-1.2): (1.4-1.6), and more preferably (1.05-1.15): (1.45-1.55). In an embodiment of the present invention, the type of the substance providing formaldehyde monomer may be paraformaldehyde; the molar ratio of the formaldehyde monomer in the cardanol and the substance providing formaldehyde monomer may be 1.1:1.5, 1.2:1.6, 1.15:1.6 or 1.05:1.45.

[0033] In the present invention, the temperature for adding the substance providing the formaldehyde monomer is preferably 75 to 90°C.

[0034] In the present invention, the process of adding the substance providing formaldehyde monomer is preferably performed in batches, and the number of batch additions is preferably 4 times.

[0035] In the present invention, the process of the Mannich reaction is preferably: first react at a temperature of 100-105°C for 1-2h, and then react at a temperature of 145-150°C for 2.5-3.5h; more preferably: first react at a temperature of 101-103°C for 1-2h, and then react at a temperature of 146-148°C for 2.8-3.2h. In an embodiment of the present invention, the temperature of the first step of the Mannich reaction can be 100°C, 105°C, 103°C or 105°C, and the time can be 2h, 1h, 1.5h or 1.8h; the temperature of the second step of the Mannich reaction can be 145°C, 146°C, 147°C or 150°C, and the time can be 3h, 3.5h or 2.5h.

[0036] After the Mannich reaction is completed, the present invention also preferably includes cooling to the temperature of the dehydration reaction. The present invention has no special limitation on the cooling process, and the process well known to those skilled in the art can be used.

[0037] In the present invention, the temperature of the dehydration reaction is preferably 100-105°C, more preferably 101-103°C; the vacuum degree is preferably 2-3kPa; the time is preferably 40-50min, more preferably 43-46min. In an embodiment of the present invention, the temperature of the dehydration reaction can be 100°C, 105°C or 103°C, the vacuum degree can be 2-3kPa, and the time can be 50min, 40min or 45min.

[0038] In the present invention, the temperature for adding the accelerator is preferably 65-70°C, more preferably 66-68°C; the accelerator preferably includes one or two of 2,4,6-tris(dimethylaminomethyl)phenol, triethanolamine and N,N-dimethyl-1,3-propylenediamine. When the accelerator is two of the above specific selections, the present invention does not have any special restrictions on the ratio of the above specific substances, and can be mixed in any ratio. In the present invention, the mass of the accelerator is preferably 2-4% of the total mass of the cardanol, tetrazolium-5-acetylhydrazine and the substance providing the formaldehyde monomer. In an embodiment of the present invention, the temperature for adding the accelerator may be 70°C, 69°C, 68°C or 65°C; the type of the accelerator may be 2,4,6-tris(dimethylaminomethyl)phenol, triethanolamine, 2,4,6-tris(dimethylaminomethyl)phenol N,N-dimethyl-1,3-propylenediamine in a mass ratio of 1:1, triethanolamine and N,N-dimethyl-1,3-propylenediamine in a mass ratio of 1:1, or triethanolamine and 2,4,6-tris(dimethylaminomethyl)phenol in a mass ratio of 1:1; the mass of the accelerator may be 2%, 2.5%, 3% or 4% of the total mass of the cardanol, tetrazolium-5-acetylhydrazine and the substance providing the formaldehyde monomer.

[0039] The present invention has no special limitation on the adding method of the accelerator, and the accelerator can be added in a method well known to those skilled in the art.

[0040] After adding the accelerator, the present invention further preferably comprises stirring, and the stirring temperature is preferably 65-70° C., and the time is preferably 1-2 hours. In an embodiment of the present invention, the stirring temperature can be 70° C., 69° C., 68° C. or 65° C., and the time can be 1.6 hours, 1 hour, 1.5 hours or 2 hours.

[0041] The present invention also provides the application of the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent described in the above technical solution or the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent prepared by the preparation method described in the above technical solution in the field of coating. In the present invention, the application field is preferably the field of epoxy coatings.

[0042] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Example 1

[0044] In an inert atmosphere (the type of inert atmosphere is N 2 ), 302g of cardanol (1mol) and 156.2g of tetrazole-5-acetylhydrazine (1.1mol) were heated to 90°C and mixed until completely dissolved, then cooled to 75°C, and 42g of paraformaldehyde (molar amount of formaldehyde monomer: 1.4mol) was added in batches (in 4 batches) at a temperature of 75-90°C, and the temperature was raised to 100°C for reaction for 2h, and then the temperature was raised to 145°C for reaction for 3.5h; the temperature was lowered to 100°C, and the vacuum degree was reduced to 2-3kPa, and then decompression and dehydration were performed for 50min, and after cooling to 65°C, 10g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol was added, and the mixture was stirred and mixed for 2h to obtain a cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure;

[0045] Figure 1 is the infrared spectrum of the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent described in Example 1, Figure 1 It can be seen that the figure is located at 3295cm -1 The peak at is -NH 2 Stretching vibration peak of NH in 2927cm -1 The peak at 1616cm belongs to the stretching vibration peak of -CH in the alkyl chain at the tail of cardanol; -1 、1581cm -1 The peaks at 1456 cm are the absorption peaks of -N=N and -C=N structures in monomeric amines; -1 The peak at belongs to the -CH out-of-plane bending vibration, indicating that the cardanol aldehyde amine epoxy resin curing agent was successfully synthesized.

[0046] The viscosity test was carried out at 25°C according to "Determination of Viscosity of Adhesives" GB / T2794-1995. The test results were: viscosity was 18600 mPa·s. The amine value was determined by the perchloric acid method to be 576.4 mg·KOH / g.

[0047] Example 2

[0048] In an inert atmosphere (the type of inert atmosphere is N 2), 332.2g of cardanol (1.1mol) and 170.4g of tetrazole-5-acetylhydrazine (1.2mol) were heated to 100°C and mixed until completely dissolved, cooled to 80°C, and 45g of paraformaldehyde (molar amount of formaldehyde monomer: 1.5mol) was added in batches (in 4 batches) at a temperature of 75-90°C, and the temperature was raised to 105°C for reaction for 1h, and then the temperature was raised to 150°C for reaction for 2.5h; the temperature was lowered to 105°C, and the vacuum degree was reduced to 2-3kPa, and then decompression and dehydration were performed for 40min, and after cooling to 70°C, 21.9g of accelerator triethanolamine was added, and the mixture was stirred and mixed for 1h to obtain a cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure;

[0049] The viscosity test was carried out at 25°C in accordance with "Determination of Viscosity of Adhesives" GB / T2794-1995. The test results were: the viscosity was 17900 mPa·s, and the amine value was determined by the perchloric acid method to be 570.7 mg·KOH / g.

[0050] Example 3

[0051] In an inert atmosphere (the type of inert atmosphere is N 2 ), 362.4g of cardanol (1.2mol) and 184.6g of tetrazole-5-acetylhydrazine (1.3mol) were heated to 95°C and mixed until completely dissolved, then cooled to 78°C, and the temperature was controlled at 75-90°C, and 48g of paraformaldehyde (molar amount of formaldehyde monomer: 1.6mol) was added in batches (in 4 batches), and the temperature was raised to 103°C for reaction for 1.5h, and then the temperature was raised to 147°C for reaction for 3h; the temperature was lowered to 103°C, and the vacuum degree was reduced to 2-3kPa, and then decompression and dehydration were performed for 45min, and after cooling to 68°C, 8.93g of accelerator 2,4,6-tris(dimethylaminomethyl)phenol and 8.93g of N,N-dimethyl-1,3-propylenediamine were added, and the mixture was stirred and mixed for 1.5h to obtain a cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure;

[0052] The viscosity test was carried out at 25°C according to "Determination of Viscosity of Adhesives" GB / T2794-1995. The test results were: the viscosity was 14600 mPa·s, and the amine value was determined by the perchloric acid method to be 582.3 mg·KOH / g.

[0053] Example 4

[0054] In an inert atmosphere (the type of inert atmosphere is N 2), 347.3g of cardanol (1.15mol) and 177.5g of tetrazole-5-acetylhydrazine (1.25mol) were heated to 97°C and mixed until completely dissolved, then cooled to 77°C, and the temperature was controlled at 75-90°C, and 48g of paraformaldehyde (molar amount of formaldehyde monomer: 1.6mol) was added in batches (in 4 batches), and the temperature was raised to 105°C for reaction for 1.8h, and then the temperature was raised to 146°C for reaction for 3.5h; the temperature was lowered to 105°C, and the vacuum degree was reduced to 2-3kPa, and then decompression and dehydration were performed for 45min, and after cooling to 69°C, 7.16g of accelerator triethanolamine and 7.16g of N,N-dimethyl-1,3-propylenediamine were added, and the mixture was stirred and mixed for 1.6h to obtain a cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure;

[0055] The viscosity test was carried out at 25°C according to "Determination of Viscosity of Adhesives" GB / T2794-1995. The test results showed that the viscosity was 15500 mPa·s. The amine value was determined by the perchloric acid method and was 577.4 mg·KOH / g.

[0056] Example 5

[0057] In an inert atmosphere (the type of inert atmosphere is N 2 ), 317.1g of cardanol (1.05mol) and 163.3g of tetrazole-5-acetylhydrazine (1.15mol) were heated to 95°C and mixed until completely dissolved, then cooled to 75°C, and 43.5g of paraformaldehyde (molar amount of formaldehyde monomer: 1.45mol) was added in batches (in 4 batches) at a temperature of 75-90°C, and the temperature was raised to 100°C for reaction for 1.5h, and then the temperature was raised to 150°C for reaction for 2.5h; the temperature was lowered to 105°C, and the vacuum degree was reduced to 2-3kPa, and then decompression and dehydration were performed for 45min, and after cooling to 70°C, 5.98g of accelerator triethanolamine and 5.98g of 2,4,6-tris(dimethylaminomethyl)phenol were added, and the mixture was stirred and mixed for 1.6h to obtain a cardanol aldehyde amine epoxy resin curing agent containing a tetrazole structure;

[0058] The viscosity test was carried out at 25°C in accordance with "Determination of Viscosity of Adhesives" GB / T2794-1995. The test results showed that the viscosity was 15500 mPa·s. The amine value was determined by the perchloric acid method to be 504.3 mg·KOH / g.

[0059] Test Case

[0060] The tetrazole-containing cardanol aldehyde amine epoxy resin curing agent prepared in Examples 1 to 5 was mixed with epoxy resin E51 (matched at an active hydrogen equivalent of 1:1) to prepare a 100 μm glass strip according to GN / T 13452.2-2008 "Determination of film thickness of paints and varnishes"; the glass strip was cured in a constant temperature and humidity chamber at 25° C. for 12 hours (film thickness of 100 μm), and the drying time after curing is shown in Table 1:

[0061] Table 1 Varnish drying time of glass strips

[0062] Example 1 Example 2 Example 3 Example 4 Example 5 Gel time 1.3 0.9 1.1 1.1 1.4 Dry time 2.2 1.6 1.7 1.8 2.5 Working time 3.7 2.7 3.1 3.4 3.9

[0063] The tetrazole-containing cashew phenol aldehyde amine epoxy resin curing agent prepared in Examples 1 to 5 and epoxy resin E51 (matched at an active hydrogen equivalent of 1:1) were diluted with a total amount of 15% of a xylene-n-butanol mixed solution (xylene: n-butanol = 3:1), stirred evenly to obtain an epoxy coating, and sprayed evenly onto a tinplate by air spraying. The cross-cut adhesion was tested according to GB / T9286-1998 "Cross-cut test for paint and varnish film"; the flexibility was tested according to GB / T 1731-1993 "Determination of film flexibility"; the impact resistance was tested according to GB / T1732-1993 "Determination of film impact resistance"; the pencil hardness of the paint film was tested according to GB / T 6739-1996 "Determination of film hardness pencil method"; the pencil hardness of the paint film was tested according to GB / T 1771-2007 "Determination of neutral salt spray resistance of paints and varnishes" tests the salt spray resistance for 1000 hours. The test results are shown in Table 2:

[0064] Table 2 Performance parameters of the tetrazole-containing cashew phenol aldehyde amine epoxy resin curing agent described in Examples 1 to 5

[0065] Test items Example 1 Example 2 Example 3 Example 4 Example 5 Film thickness, μm 25±2 25±2 25±2 25±2 25±2 Cross-cut Adhesion 0 0 0 0 0 Pencil hardness 2H H 2H H 2H Impact resistance, cm 100 100 100 100 100 Flexibility, mm 1 1 1 1 1 1000h corrosion width, mm 0.77 0.63 0.71 0.68 0.81

[0066] It can be seen from Tables 1 to 2 that the cashew phenol aldehyde amine epoxy resin curing agent containing a tetrazole structure of the present invention has a faster curing speed, which can shorten the construction period of downstream applications; at the same time, it has very excellent mechanical properties and corrosion resistance: the impact strength reaches 100cm, the cross-cutting adhesion reaches level 0, the flexibility reaches 1mm, the hardness is above level H, and the average salt spray corrosion resistance width of 1000h is 0.72mm; in summary, the cashew phenol aldehyde amine epoxy resin curing agent containing a tetrazole structure of the present invention is used in combination with E51 epoxy resin, and has a fast curing speed and excellent mechanical properties.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A tetrazole-containing cardanol aldehyde amine epoxy resin curing agent, characterized in that: It has a structure shown in Formula 1 or Formula 2:

2. The preparation method of the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent according to claim 1, characterized in that: The following steps are involved: In an inert atmosphere, cardanol and tetrazole-5-acetylhydrazine are mixed, a substance providing formaldehyde monomer is added, and a Mannich reaction and a dehydration reaction are sequentially performed, and then an accelerator is added to obtain the cardanol aldehyde amine epoxy resin curing agent with a tetrazole structure.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the cardanol, tetrazole-5-acetylhydrazine and the formaldehyde monomer in the substance providing the formaldehyde monomer is (1.0-1.2): (1.1-1.3): (1.4-1.6).

4. The preparation method according to claim 2 or 3, characterized in that: The substance providing formaldehyde monomer includes paraformaldehyde or a formaldehyde aqueous solution with a mass concentration of 37%.

5. The preparation method according to claim 2, characterized in that: The mixing temperature is 90-100°C; the adding temperature of the substance providing formaldehyde monomer is 75-90°C.

6. The preparation method according to claim 2, characterized in that: The process of the Mannich reaction is: first react at a temperature of 100-105° C. for 1-2 hours, and then react at a temperature of 145-150° C. for 2.5-3.5 hours.

7. The preparation method according to claim 2, characterized in that: The temperature of the dehydration reaction is 100-105° C., the vacuum degree is 2-3 kPa, and the time is 40-50 min.

8. The preparation method according to claim 2, characterized in that: The accelerator includes one or two of 2,4,6-tris(dimethylaminomethyl)phenol, triethanolamine and N,N-dimethyl-1,3-propylenediamine.

9. The preparation method according to claim 2 or 8, characterized in that: The mass of the accelerator is 2-4% of the total mass of the cardanol, tetrazole-5-acetylhydrazine and the substance providing the formaldehyde monomer.

10. Use of the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent according to claim 1 or the tetrazole-containing cardanol aldehyde amine epoxy resin curing agent prepared by the preparation method according to any one of claims 2 to 9 in the field of coating.

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